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Seminar Programme

We encourage visitors to give a research seminar while on La Palma. Please contact your support astronomer, Ovidiu Vaduvescu or Cecilia Farina if you would like to give a presentation. We invite staff from other institutions on site to attend. These seminars take place in our sea-level base in Santa Cruz de La Palma, on the 6th floor of Mayantigo building. Some of these seminars are organised together with Mercator telescope.

Other institutions at the Roque de Los Muchachos Observatory organise seminars, such as TNG and NOT or GTC, at a nearby location in San Antonio (10 min by car/bus from Santa Cruz, see next Google map). Other seminars are organized by the IAC in La Lagune, Tenerife, usually being broadcasted and archived using online streaming video or videoconferencing facilities. The La Palma astronomy student journal club also organises seminars.

Seminars in 2020

Oncoming Seminars:

To be announced soon, please check later.

Past Seminars:

Date: Tuesday 10 March 2020 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Early cluster evolution
Speaker, Affiliation: Prof. Dr. Pavel Kroupa, The Argelander-Institut fur Astronomie (AIfA), University of Bonn, Germany
Stars can be mathematically modelled as being formed as multiple systems formed at the same time in spherical embedded clusters. Observational constraints imply these to be very compact with half mass radii rh/pc = 0.1(M/Msun)^0.13 and a wide range of stellar masses M (10 to many millions). These embedded clusters need to expand within a few Myr to achieve the radii of open and globular clusters and this can only be achieved by the expulsion of a significant amount of residual gas. The stellar-dynamical processes within the embedded clusters shape the multiplicity properties of Galactic-field stars and low-mass dwarf galaxies ought to have a much higher binary fraction than massive elliptical galaxies. Massive stars, formed in the mass segregated embedded clusters, eject each other efficiently from their birth clusters. These stellar-dynamical processes may be important for the emergence of multiple populations in embedded clusters which are not older than a few Myr by modulating infalling molecular gas into the cluster along molecular cloud filaments. They result in a field-population of runaway and slow moving O stars which is largely consistent with the observed isolated O stars.
Slides: PDF. Additional material: Cluster animation 3000 stars; Cluster animation 30000 stars

Date: Friday 21 February 2020 Time: 10:30 hrs Place: Mayantigo building 6th floor meeting room
Title: Juan Valderrama y Aguilar, a forgotten pioneer of the Astronomy in the Canaries
Speaker, Affiliation: Dr. Jorge Sanchez Almeida, Instituto de Astrofisica de Canarias (IAC)
Early 21st century, on a date still undetermined. A stranger leaves at the IAC library seven logbooks with astronomical observations made more than a hundred years ago (1886-1891), in Madrid and Santa Cruz de Tenerife, by someone called Juan Valderrama y Aguilar (JVyA). The logbooks sleep in the library for another ten years until we discovered them by chance. We were surprised by the quality and meticulousness of the drawings that illustrate the logbooks, the fact that Juan Valderrama's papers were cited in the ADS (Astrophysics Data System) and, above all, that the community of professional astronomers working in the canaries had never heard of him. Could JVyA be an astronomer living in Santa Cruz de Tenerife whose existence has remained unnoticed to the official history of the astronomy in the Canary Islands? (Science was not a major Canarian export in those days, so, it would be like finding a needle in a haystack). The answer to the previous question is "yes." JVyA is a complete stranger to the official history, but it has a scientific biography worth remembering. Outside the local official science and the university environment, JVyA was, however, well connected to the world of modern astronomy of the time. His first paper can be regarded as the first astronomy paper by a Canarian in an international journal (Valderrama, 1886, L'Astronomie, Vol. 5, Page 388), and was published when he was only 17. M. Vazquez Abeledo and I wrote a brief biography of JVyA that claims its figure of astronomer, which was published by Cabildo de Tenerife in 2018. In the talk I will present JVyA as well as some of his astronomical contributions.
Slides: PDF

Seminars in 2019

Date: Tuesday 10 December 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Using Galactic Archaeology to Uncover the Formation History of S0 Galaxies
Speaker, Affiliation: Thomas Davison, ING and PhD student, University of Central Lancashire, UK
Of the many galaxy types in the universe, S0's are amongst the most mysterious. The exact mechanism of S0 galaxy formation is hotly debated with contradictory formation methods proposed. In my most recent work, I have used the EAGLE cosmological simulations to predict the distribution of ex-situ stellar populations within S0 galaxies. These predictions were set in context with observable parameters such as stellar mass and surface brightness, which has allowed us to compare to observational data. By utilising recent advancements in full spectral fitting software, I have extracted the fractions of ex-situ populations from low signal-to-noise galaxies imaged in the SDSS survey, and calibrated these fractions using the EAGLE simulations. With a robust pipeline for extracting ex-situ populations from galaxies, I now intend to apply the same technique to resolved S0's using MUSE IFU data, to build maps of ex-situ locations within galaxies. Combining this information with full star-formation history (extracted during the spectral fitting process) we expect to accurately identify the specific methods of formation for S0 galaxies.
Slides: PDF Additional material: EAGLE simulations multi component (74 MB, avi movie)

Date: Friday 29 November 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Extremely low-mass white dwarfs : the story so far
Speaker, Affiliation: Alina Istrate, Radboud University, Nijmegen, Netherlands
Extremely low-mass white dwarfs (ELM WDs) represent a new class of helium-core white dwarfs characterized by a mass smaller than ~0.3 Msun and with surface gravity in the range 5 < log g < 7. Today we know of the existence of more than 100 such objects, with the majority of them found in binary systems with more massive CO WDs. From an evolutionary point of view, they are most likely the result of binary evolution as they are not expected to form from single stars within a Hubble time. The new wealth of data raised questions regarding some puzzling properties of these stars such as, for example, the presence of metals in the atmospheres of young bloated ELM proto-WDs and the recent discovery of pulsations in a couple of proto-ELMs. In this talk I will review the latest theoretical and observational efforts regarding the formation and evolution of (proto-) ELM WDs.

Date: Thursday 7 November 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: ISIS neutron and muon source: an insight inside the materials
Speaker, Affiliation: Diego Alba Venero, UKRI, STFC, United Kingdom
The discovery of new materials is driving force in the progress of civilization. Understanding the science behind their properties is of paramount importance for the development of new materials which raise some extreme appealing for basic research. At STFC ISIS laboratories we use neutrons and muons for studying the structure and dynamics of materials of any kind, from exotic magnetic phases to drug delivery system or planet formation.
Slides: PDF

Date: Friday 11 October 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Detecting dark matter
Speaker, Affiliation: Prof. Pavel Kroupa, The Argelander-Institut fur Astronomie (AIfA), University of Bonn, Germany & Astronomical Institute, Charles University, Prague, Czech Republic
Neither the standard model of particle physics nor direct detection experiments have yielded any need nor any evidence for the existence of cold or warm dark matter particles. These are only hypothesised to exist if general relativity is extrapolated from the Solar-system scale to galaxies and beyond. Cases in point are the observed non-Keplerian, flat rotation curves of disk galaxies which are the by far dominant population of galaxies and the missing mass phenomenon in galaxy clusters. I will discuss the possibility of confirming the existence of such dark matter particles using Chandrasekhar dynamical friction. Explicit test cases are the satellite galaxies of the Milky Way, the M81 group of galaxies and Hickson compact groups. The observed positions and motion of the galaxies in these systems show that the action of dynamical friction on the speculative dark matter halos is not evident in the data. The systems behave dynamically as if the extended dark matter halos do not exist. Thus, the orbits of the Milky Way satellite galaxies do not seem to be decaying sufficiently with time, nor are the compact galaxy groups merging.  Corroborative evidence comes from the highly symmetric distribution of all non-satellite galaxies in two 1.5Mpc extended, 50kpc-thick planes in the Local Group around the axis joining the Milky-Way and Andromeda galaxies. This symmetric arrangement of matter on Mpc scales remains entirely unexplained by current cosmological and dynamical theory, and is largely ignored by the community, despite being based on the very best extragalactic data at hand (because the involved galaxies are the nearest galaxies to the Milky Way). Further corroborative evidence comes from the five nearest major galaxies having three highly pronounced disk-of-satellite systems, which together falsify the standard dark-matter-based cosmological model with more than five sigma confidence.  The evidence thus gathered consistently and unanimously shows that dark matter particles cannot be present. The observed dynamics therefore cannot be Newtonian, but must, in the classical limit, essentially be Milgromian, and cosmological theory needs a major repositioning. As a consequence, our ability to deduce the physics of galaxy evolution from observation is probably wrong as it is at present based on assuming the standard cosmological model is valid.
Slides: PDF

Date: Monday 7 October Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: The impact of bars on star formation in disc galaxies
Speaker, Affiliation: Prof. Phil James, Astrophysics Research Institute, Liverpool John Moores University
Bars have long been known to have a strong influence on galaxy evolution, e.g. as drivers of so-called secular processes. In recent years, colleagues and I have been studying the effect of strong bars on the spatial distributions and overall rates of star formation within disc galaxies, motivated by the discovery of a characteristic suppression pattern we term the 'star formation desert'. I will describe tests of the causes and implications of this behaviour, using both observations and computer simulations, and its potential use in age dating bars and probing stellar radial migration.

Date: Tuesday 10 September 2019 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room

Title: The systematically varying stellar IMF and some implications thereof

Speaker, Affiliation: Prof. Pavel Kroupa, The Argelander-Institut fur Astronomie (AIfA), University of Bonn, Germany & Astronomical Institute, Charles University, Prague, Czech Republic
Some ultra-compact dwarf galaxies have large dynamical mass to light (M/L) ratios and also appear to contain an overabundance of LMXB sources, and some Milky Way globular clusters have a low concentration and appear to have a deficit of low-mass stars. These observations can be explained if the stellar IMF becomes increasingly top-heavy with decreasing metallicity and increasing gas density of the forming object. The thus constrained stellar IMF then accounts for the observed trend of metallicity and M/L ratio found amongst M31 globular star clusters. Since the galaxy-wide IMF (gwIMF) is made up of the IMFs of all embedded cluster forming in a galaxy, it becomes possible to calculate the gwIMF. This calculation shows that the systematically varying IMF accounts for the overall shift of the observationally deduced gwIMF from top-light to top-heavy with increasing star formation rate amongst galaxies. This is an important self-consistency check between star formation on pc scales and galaxy-wide stellar populations. The implications of this for observations of extremely young very massive star-burst clusters observed at a high redshift which may appear quasar-like will be discussed based on our recent work (Jerabkova et al. 2017).
Slides: PDF Additional material: Cluster animation 3000 stars; Cluster animation 30000 stars

Date: Friday 30 August 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Commissioning of a new ING DIMM at ORM
Speaker, Affiliation: MSc Student Luke Holden, ING and Sheffield University, UK
Project advisor: Neil O'Mahony, Isaac Newton Group

For a number of years, three different DIMMs have provided seeing measurements at three different locations at ORM. These include the ING's RoboDIMM near the William Herschel Telescope, the TNG'S DIMM near the Telescopio Natizional Galileo and the IAC's DIMM near the GranTeCan. In September 2018 the ING commissioned a new DIMM, 'R2D2', located in the ING DIMM tower near the WHT. R2D2 is based off of the TNG DIMM and represents an improvement over the older RoboDIMM in many ways. In this talk i'll discuss the problems we faced in the commissioning of R2D2, how we solved them and the current status of the DIMM. In addition, I'll talk about local seeing variations across the observatory site using seeing measurements from R2D2 and the other DIMMs.
Slides: PDF

Date: Friday 30 August 2019 Time: 11:30 hrs Place: Mayantigo building 6th floor meeting room
Title: Evolution of light pollution at ORM over the last decade
Speaker, Affiliation: MSc Student Luke Holden, ING and Sheffield University, UK
Project advisor: Dr. Chris Benn, Isaac Newton Group

The skies above ORM are amongst the darkest in the world, thanks to the strict regulation of street lights and other light sources on La Palma. This lighting mostly consists of low-pressure sodium (LPS) lamps, which narrowly emit NaD (5890/6A) doublet photons. In this talk, I will discuss the use of INT and WHT archival data to measure the evolution of the NaD line intensity over the past three decades at ORM, as well as how this intensity depends on weather conditions and position across the sky.
Slides: PDF

Date: Thursday 25 July 2019 Time: 12:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Gemini Observatory: where we are now, and future prospects
Speaker, Affiliation: Dr. Rene Rutten, Associate Director of Chile Operations, Gemini Observatory

The Gemini telescopes have been in operation for nearly two decades, and during that time they have made a very significant impact in astronomical discoveries through innovative instrumentation combined with exploring novel operational methods. But the world of astronomy is very dynamic and new challenges are on the horizon. Two major changes are planned for the future to meet those challenges: preparing the observatory for the era of multi-messenger astronomy, and the prospect of becoming a key player in a large, new organization, the National Center for Optical-Infrared Astronomy, that will encompass several federally funded ground-based telescopes. I will highlight the current status of Gemini Observatory, and its near-term instrumentation and operational prospects. Next, I will explain our future plans to be prepared for the era of multi-messenger astronomy, and how the plans are unfolding for the new National Center that is being formed.

Date: Tuesday 11 June 2019 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: THELI image processing of faint dwarf elliptical galaxies observed in near infrared
Speaker, Affiliation: Drd. Viktoria Pinter, The University of Craiova, Romania; ING Erasmus+ visiting student
Abstract: Dwarf galaxies are the most common types in the Universe. They can be separated into two main groups: early-type dwarfs (ETD) which include dwarf ellipticals (dEs) and dwarf spheroidals (dSphs), and late- type dwarfs (LTD) which include star forming dwarf irregulars (dIs) and blue compact dwarfs (BCDs). As some previous work suggested that strong evolutionary links between ETDs and LTDs (Vaduvescu and McCall, 2005) and between dEs and dSphs (Ivkovich and McCall, 2019), the aim of my PhD thesis is to study dEs using deep near infrared imaging mainly using a few existing archives. Upon revising the literature, my galaxy sample contains 131 dEs: 19 in the Local Volume (LV), 34 in Virgo, 48 in Coma and 30 in Fornax clusters, which probably represent a "complete" sample of dEs in the nearby Universe. Recently we observed 11 of these LV members using the WHT-LIRIS, collecting huge amount of data for the remaining 120 from archival images (about 5 TB). The data mining pre-selection was made using the MASFO online tool, then using the ESO and CADC databases to download the raw FITS images. We used mainly THELI for the image reduction, then IRAF to solve a few problematic cases. The whole image reduction took quite much time and needed lots of space, and we used 3 computers in this process. To derive photometric zero-points, we used the Photometry Pipeline script written by Michael Mommert. During this seminar I will present some THELI guidlines for succesful data reduction in NIR, the photometry pipeline for deriving the automated zeropoint and I will show some reduced images, including the WHT targets which probably map most deeply 11 dEs from the LV to be studied in my thesis further.

Date: Monday 6 May 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: New Approaches to Untangle the Accretion Histories of Galaxies
Speaker, Affiliation: Mark. D. Norris, University of Central Lancashire, UK
Abstract: I will discuss complimentary approaches to reconstruct the assembly histories of galaxies by studying the concentrated (i.e. star cluster/UCD) and diffuse stellar populations of their outer regions.

Date: Friday 26 April 2019 Time: 10:30 hrs Place: Mayantigo building 6th floor meeting room
Title: HARPS3 and the Terra Hunting Experiment at the INT
  • Didier Queloz
  • Samantha Thompson
  • John Young
  • Martin Fisher
Abstract: The Terra Hunting Experiment consortium is currently building the High Accuracy Radial-velocity Planet Searcher 3 (HARPS3) spectrograph and will be refurbishing the Isaac Newton Telescope to enable a robotic operation. Over the next 2.5 years the project will be in an intensive manufacturing, assembly, integration and verification stage. We will also be preparing for the start of the Terra Hunting Experiment - a 10 year radial velocity survey on our nearest solar-like stars with the aim of finding "another Earth". We will present a comprehensive description of the project, including: an overview of the aims and strategies for the Terra Hunting Experiment, a description of the high resolution spectrograph HARPS3 and its software systems and the plans for the roboticization of the Isaac Newton Telescope.
  • HARPS3: Terra Hunting Experiment, HARPS-3 @ INTscience - Didier Queloz PDF
  • HARPS3: High Accuracy Radial-velocity Planet Searcher 3 - Samantha Thompson PDF
  • HARPS3: THE@INT Software Systems - John Young PDF
  • HARPS3: Telescope Refurbishment Work-package - Martin Fisher PDF

Date: Thursday 31 January 2019 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Cool and Luminous Outbursts from Merging Binary Stars
Speaker, Affiliation: Dr Ondrej Pejcha, Charles University, Czech Republic
Abstract: There is mounting evidence of circumstellar material (CSM) distributed in disks and rings around many massive stars, supernovae, classical novae, and other interesting stellar objects. The origin of this CSM is often attributed to interactions within a binary star system, including poorly-understood processes such as the common envelope and stellar mergers. Recently, a connection was established between these astrophysically critical, catastrophic binary star interactions and a group of astronomical transients characterized by their red color and the luminosity in the gap between novae and supernovae. I will present an exploration of the dynamics of outflows from mass-losing binary stars and the associated menagerie of transients. I will discuss how is the binary enshrouded in a "death spiral" outflow and how does it explain many puzzling observed phenomena.

Seminars in 2018

Date: Monday 10 Dec 2018 Time: 14:00 hrs Place: Mayantigo building 6th floor meeting room
Title: First Contact: Unravelling the nature of Interstellar Object 'Oumuamua
Speaker, Affiliation: Alan Fitzsimmons, Astrophysics Research Centre, Queen's University Belfast, Northern Ireland.
Abstract: The first Interstellar Object to be discovered passing through our Solar system was found in October 2017. By the time it was announced it was already 22nd magnitude and fading. The resulting scramble for imaging and spectroscopy, using telescopes including the WHT, revealed a body that matched some of our expectations, but that differed significantly in other aspects. These studies have given considerable insight into our alien visitor, now named 'Oumuamua. But many questions remain as to its origin, evolution and physical nature. In this seminar I will explain why we expected to see something like 'Oumuamua at some point, what we have know and don't know, and what we might expect to see in the future.
Slides: PDF and 'Oumuamua orbit animation

Date: Friday 30 Nov 2018 Time: 14:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Star Formation History of the Bar and the Inner Disk of the Large Magellanic Cloud
Speaker, Affiliation: Lara Monteagudo, Instituto Astrofisico de Canarias (IAC) and Isaac Newton Group (ING)
Abstract: Our objective is to study the structure and evolution of the LMC through the analysis of its stellar populations. For this study we have color-magnitude dia- grams (CMDs) reaching the oldest main sequence turn-offs (oMSTO), even in the most crowded fields. We have eleven fields covering a large range of galactocentric distances. Two of the fields probe the bar, while the others are located in the inner disk at various distances and azimuths. Overall we find a surprising homogeneity in the SFH of the bar fields, among disk fields, and also between bar and disk fields, which means that no event of star formation can be identified with the formation of the LMC bar. Upon closer examination of the SFR of the eleven fields, we found three different groups of fields depending on their position in the inner region of the LMC. The youngest fields are in the bar, while those that are located in the inner disk are older. We also found that the fields located in the north and south arms are slightly younger than the inner disk fields, but somewhat older than the bar fields. We also searched for radial gradients in the SFH over a larger range of galacto- centric distance, from the very centre of the LMC, out to the radius explored by Meschin et al. (2014). Interestingly, we found that the global age indicators show an approximately at behaviour between 1 and 5 degrees from the centre, but turn to indicate an increasing mean age at larger galactocentric distances.

Date: Thursday 22 Nov 2018 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: On the formation, evolution, and destruction of minor planetary bodies
Speaker, Affiliation: Thomas Wilson, University College London (UCL) and Isaac Newton Group (ING).
Abstract: Minor planetary bodies can provide a wealth of information on the history and future of planetary systems, from the formation conditions in the solar nebula to the destruction processes of planets. In this talk I will discuss the two main projects of my PhD: the study of water in Solar System comets, and the search for asteroid debris disks around white dwarfs. Comets have long been heralded as pristine objects left over from the formation of the Solar System. However, there is a fundamental question yet to be concretely answered: is the observed composition indicative of formation or evolutionary processes? Isotopic and isomeric ratios, such as Deuterium/Hydrogen and Water Ortho-to-Para, can be good probes as evolutionary processes are not thought to change these values greatly. Some results point towards abundances being typical of primitive material, but their methods have recently been proven not to be as reliable as once thought. In the first half of the seminar I will present Herschel/SPIRE observations of four comets and discuss the how the observed non-typical Water Ortho-to-Para ratios have helped change our understanding of evolutionary processes in comets. While exoplanet surveys over recent years have advanced the field considerably, there is still a limitation in most methods, which cannot directly probe planetesimal composition. Planetary systems around white dwarfs have been known for a couple of decades and are inferred to exist by the presence of atmospheric metals. These metals can only be explained by ongoing accretion, being a proxy for the composition of the infalling planetesimal. Another possible indicator of planetesimals are a circumstellar dust disks, often observed in the infrared. By searching for destroyed planetesimals via these indicators, we can infer planetary system architectures, dynamics, and frequency. In the second half of my talk I will present the analysis of the largest, unbiased Spitzer and Hubble survey of observations of polluted white dwarfs and its implications on our knowledge of the fate of planetary systems.
Slides: PDF

Date: Monday 05 Nov 2018 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Storms or systematics? Using ground-based telescopes to search for atmospheric variability in hot Jupiters
Speaker, Affiliation: Matthew Hooton, Astrophysics Research Centre at Queen's University Belfast.
Abstract: Detecting and measuring thermal emission from exoplanets during their secondary eclipses has established itself as an important tool for studying exoplanet atmospheres, with over a hundred published results to date. Making this measurement over a range of wavelengths allows models of their emission spectra to be constructed, which alludes to atmospheric features such as chemical composition, thermal structure and circulation efficiency. Unfortunately, repeat observations of secondary eclipses routinely yield depths that significantly disagree. Without understanding the source of these disagreements, which could arise due to systematic errors or genuine atmospheric variability in the exoplanets themselves, it is difficult to reliably constrain the atmospheric properties of these exoplanets. I will present results from the QUB secondary eclipse campaign, which aims to address this problem using large programmes on 2m-class telescopes such as the INT and LT. I will describe our past and future observations of WASP-12b, a hot Jupiter with a 10-year history of confounding observers and theorists, as well as our initial atmospheric categorisation of the newly-discovered KELT-16b. I will also present our ultraviolet secondary eclipse of the recently discovered KELT-9b -- the hottest known exoplanet.

Date: Wedenesday 05 Sep 2018 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Exoplanets in Ondrejov, ground based support of space missions
Speaker, Affiliation: Dr. Petr Kabath, Astronomical Institute of the Czech Academy of Sciences, Czech Republic
Abstract: Exoplanet group in Ondrejov, CZ was founded in 2016. The astronomical Institute Ondrejov operates a 2-m telescope equipped with an Echelle spectrograph. In the seminar an overview about the potential of our ground based support program for exoplanetary missions will be presented along with first results from 2017/2018 campaign. Furthermore, our institute in cooperation with Tautenburg Observatory and Universidad Catolica de Chile plans to design a new spectrograph for 1.52m telescope at ESO La Silla observatory, Chile which should contribute to candidate vetting process for PLATO in the future and most certainly also for TESS.
Slides: PDF

Date: Monday 23 April 2018 Time: 14:30 hrs Place: Mayantigo building 6th floor meeting room
Title: It came from outer space: Interstellar visitor 1I/'Oumuamua
Speaker, Affiliation: Dr. Colin Snodgrass, The Open University, UK
Abstract: Late last year there was much excitement within the planetary science community, and in the press, about the first macroscopic interstellar object to be discovered passing through our Solar System. I'll tell the story of the discovery of 1I/'Oumuamua, the scramble to observe it before it left, and what we know about it after a couple of months of rapid publication of surprising results.
Slides: PDF

Date: Friday 6 April 2018 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Testing entanglement using cosmic random numbers
Speaker, Affiliation: Dominik Rauch, Austrian Academy of Sciences and IQOQI - Institute for Quantum Optics and Quantum Information
Abstract: I will report on our Cosmic Bell test experiment we conducted in February at the ORM, where, as a premiere, we used the William Herschel Telescope and the Telescopio Nazionale Gallileo for simultaneous observations. Since the 1930s, physicists wonder whether the probabilistic quantum theory can be a complete description of nature or if we just lack the necessary information (hidden variables) for a deterministic theory. Einstein thought, quantum mechanics cannot be complete, because it would predict the strange phenomenon of entanglement. Only in the 1970s, John Stewart Bell found a way to prove the absence of any additional unknowns by probing correlations of allegedly entangled photon pairs. Since then, many Bell tests have been performed, strongly supporting quantum mechanics. However, all of these tests require certain assumptions, generally known as "loopholes". The last loophole to close is the so called "freedom of choice". It says that correlations in the choice of the measurement basis could be misinterpreted and misleadingly appear similar to entanglement. The usual approach to eliminate correlations in the setting choices, is to space like separate these events from the actual measurements. Earlier experiments used settings generated around 4us in the past. By extracting random numbers from astronomical sources we can push these limits far further. In an earlier experiment we used milky way stars, that are 600 lyr away (Handsteiner et. al, 2017). In our recent experiment we had the WHT and the TNG observe different high-redshift quasars at the same time. A entangled photon source next to the NOT was creating photon pairs, sending one photon to a receiver station to the ground floor of the WHT dome, and the other to a receiver next to TNG, implementing the actual Bell test.

Date: Monday 19 March 2018 Time: 12:00 hrs Place: Mayantigo building 6th floor meeting room
Title: New evidence for the existence of Precise Lunar Alignments in the Early Bronze Age
Speaker, Affiliation: Dr. Thomas Gough, Royal Observatory Edinburgh Site Tester 1971-1974
Abstract: Alexander Thom (1894-1985) was a Professor of Science and Engineering at Oxford University. However he became interested in megalithic remains. In particular he made many theodolite measurements of indicated foresights and orientations from standing stones. From the declinations found, he deduced that the lunar perturbation of about 9' of arc had been observed in the Early Bronze Age, c. 1700 BC. He published three books and numerous papers. His work did not meet with favour from the majority of archaeologists. Clive Ruggles assessed Thom’s work in detail finding problems with many of Thom’s claimed "lines", but acknowledged that a few of the "lines" appeared to be sound. However since chance alignments will occur and the sites assessed were widely scattered the apparently sound lines were considered probably chance. Ruggles also pointed out the apparently insuperable difficulties that the work would have entailed. As a result Thom’s work was sidelined. There has been no serious reinvestigation since Thom died. I became interested some 10 years ago. It was early recognised that all sites in restricted regions had to be assessed. In the region of Argyll together with the nearby islands of Mull and Islay strong supporting evidence for precise lunar alignments has been found.
Slides: PDF

Date: Monday 19 March 2018 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: A presentation on the Site Testing project run by The Royal Observatory Edinburgh, 1971-75: La Palma and other sites investigated.
Speaker, Affiliation: Dr. Thomas Gough, Royal Observatory Edinburgh Site Tester 1971-1974
Abstract: The aim of the project was find a good site in the northern hemisphere for optical astronomy. The core personnel were those who at the time were operating the ROE satellite tracking station run by Bennet MacInnes. He became the team leader of the site testing project. Other members of the group were either junior employees of the observatory or recruited by advertisement. The initial sites tested were a site in southern Italy and Izana on Tenerife. The most important measurements made were of sky transparency and seeing. For the latter a Polaris Trail Telescope was used; a semi fixed six inch refractor mounted on a solid base and aligned as required on the pole star. A camera mounted in place of the eyepiece was used to take ten minute exposures each clear hour; the density of the trail giving a measure of the seeing. The site in Italy proved to be disappointing. Izana was good, but it was suspected that the seeing was affected by turbulence resulting from the prevailing wind blowing up the east/west oriented ridge. It seemed that La Palma might benefit in this respect by its rounded shape. A preliminary testing of six weeks length was carried out at Fuente Nueva in 1972. The results were very encouraging. It was felt prudent to investigate other possible sites for comparison. Thus Fogo in the Cape Verde Islands, Madeira and Hawaii were each investigated. A return was made to La Palma in the autumn of 1974 now involving the Scandinavian countries. A hut was built and the site tested for a year proving the site to be of outstanding quality.
Slides: PDF

Date: Wednesday 14 February 2018 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Understanding ultra-diffuse galaxies through neutral hydrogen studies
Speaker, Affiliation: Betsey Adams ASTRON, the Netherlands Institute for Radio Astronomy and Kapteyn Astronomical Institute, Netherlands
Abstract: Ultra-diffuse galaxies (UDGs) are notable for their extreme low surface brightness nature and extended radii; they have the stellar mass and appearance of dwarf spheroidal galaxies but the stellar radii of larger galaxies like the Milky Way. While UDGs were originally identified in the cluster environment, several theoretical models suggest that UDGs are a subset of the dwarf galaxy population and should also be found in isolation. Neutral hydrogen (HI) observations are a powerful way to identify these field UDGs as existing wide-field surveys, such as the ALFALFA HI survey, have the sensitivity to detect these objects while their optical counterparts are tenuous in existing wide-field optical surveys. The HI observations also trace the kinematics of the gas, allowing a constrain on the underlying dark matter halos. As different models make predictions about both the total gas content and the underlying dark matter halo, these observations are a powerful way to distinguish between different models.

Date: Tuesday 23 January 2018 Time: 14:30 hrs Place: Mayantigo building 6th floor meeting room
Title: A new 1-m class telescope observatory project of Kerman University, Iran
Speaker, Affiliation: Dr. Saeed Doostmohammadi, Shahid Bahonar University of Kerman, Faculty of Physics, Department of Astronomy, Iran
Abstract: There are many observatories around the world including 1-m class telescopes which work on many scientific projects such as exo-planets, asteroids, Solar System, gravitational lensing, gravitational waves and many others. By using from new methods and high performance instruments, new and useful information are obtained daily. We are planing a new observatory in the Kerman province of Iran, to host a telescope in 1-m class (maybe 1.2 to 1.5m) with a modern larger field CCD camera and a spectrograph. To decide the location, we measured astronomical seeing of some suitable sites in the mountains at altitudes above 2500 m, far from light pollution of the cities and we obtained good results, around 1" seeing. Coming now for the second time to the ING, I am searching knowledge and know-how about the best telescopes, CCDs, spectrographs, dome, enclosures, manufacturers, etc, to help our project. Also, we are gathering information about the main scientific missions of our upcoming observatory and the best kind of operation of our telescope, namely classic, remotely or/and robotic.
Slides: PDF

Date: Monday 22 January 2018 Time: 11:30 hrs Place: Mayantigo building 6th floor meeting room
Title: The Pristine survey: An efficient search for extremely metal poor stars
Speaker, Affiliation: Kris Youakim, Leibniz Institute for Astrophysics Potsdam, Germany
Abstract: The most metal-poor stars in the Galaxy are relics from the first generations of star formation, and their properties can reveal key information about the formation and evolution of the Milky Way. However, only a small number of these extremely rare stars are currently known, due to the difficulty in finding them amongst the overwhelmingly more abundant stars of higher metallicity. In this talk, I will present the Pristine survey, a narrow-band photometric survey in the wavelength region around the Ca II H&K absorption lines designed to efficiently search for extremely metal-poor (EMP) stars. In the first three years of the survey, we have covered ~2,500 square degrees of sky in the northern galactic halo using the CFHT on Mauna Kea in Hawaii. The survey has also particularly benefited from ING telescopes, using the INT and WHT to obtain a sizeable spectroscopic follow-up sample. With this data, we have demonstrated success rates of 70% for finding stars with [Fe/H] < -2.5, and 22% for stars with [Fe/H] < -3.0. This represents a significant improvement upon previous searches for EMP stars, which have reported success rates of 3-4%. With this efficiency, the Pristine survey is poised to make a significant contribution to constraining the metal-poor tail of the metallicity distribution function, as well as increasing the number of known ultra metal-poor (UMP) stars in the literature. In addition, I will discuss how the Pristine survey is being used to characterise the faint dwarf galaxy population, and analyse substructure in the Galactic Halo.
Slides: PDF

Date: Wednesday 10 January 2018 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: The BlackGEM Array - looking for optical counterparts of gravitational wave sources
Speaker, Affiliation: Steven Bloemen, Radboud University (Nijmegen, The Netherlands) and Netherlands Research School for Astronomy (NOVA, The Netherlands)
Abstract: While we understand single-star evolution fairly well, our comprehension of the evolution of binary stars is still fragmentary, and theoretical models are still in development. This is particularly true for close binaries, which interact at some point in their lives. Over 50% of all stars with mass above one solar mass are in binaries, and about 25% of binary systems interact, therefore the lack of good theoretical models is very concerning. To improve such models, observational input is urgently required. Extremely-low mass white dwarfs (ELMs) are one possible outcome of binary evolution and a good example of the incompleteness of our observational sample. They were only recently discovered with less than a hundred known. Importantly, the number of known ELMs in the cool, low-mass end of the distribution is at least a hundred times lower than predicted by current theoretical models. In this talk, I will describe our efforts to find this missing population, which will empirically help to improve theoretical models and our understanding of binary systems.
Slides: PDF

Seminars in 2017

Date: Thursday 14 December 2017 Time: 11:30 hrs Place: Mayantigo building 6th floor meeting room
Title: Where are the missing cool ELMs?
Speaker, Affiliation: Ingrid Pelisoli, Universidade Federal do Rio Grande do Sul, Brasil
Abstract: While we understand single-star evolution fairly well, our comprehension of the evolution of binary stars is still fragmentary, and theoretical models are still in development. This is particularly true for close binaries, which interact at some point in their lives. Over 50% of all stars with mass above one solar mass are in binaries, and about 25% of binary systems interact, therefore the lack of good theoretical models is very concerning. To improve such models, observational input is urgently required. Extremely-low mass white dwarfs (ELMs) are one possible outcome of binary evolution and a good example of the incompleteness of our observational sample. They were only recently discovered with less than a hundred known. Importantly, the number of known ELMs in the cool, low-mass end of the distribution is at least a hundred times lower than predicted by current theoretical models. In this talk, I will describe our efforts to find this missing population, which will empirically help to improve theoretical models and our understanding of binary systems.
Slides: PDF

Date: Tuesday 14 November 2017 Time: 11:30 hrs Place: Mayantigo building 6th floor meeting room
Title: Long-period binary central stars of planetary nebulae
Speaker, Affiliation: Dr. David Jones, Instituto de Astrofisica de Canarias, CALP La Palma
Abstract: It is now clear that a binary evolutionary pathway is responsible for a significant fraction of all planetary nebulae, with some authors even going so far as to claim that binarity may be a near requirement for the formation of an observable nebula. To date, much of the work, both observational and theoretical, has focussed on the influence of close binary evolution on the formation of a planetary nebula, however there are strong indications that wide binaries will also have a strong impact.  Here, I will report on the recent studies of such wide binaries, including the discovery of three wide binary central stars using Mercator-HERMES (the only wide binary central stars to have had their periods derived spectroscopically), as well as the interesting results from barium star central stars and what they tell us about the accretion processes experienced by all barium and carbon-enhanced-metal-poor stars.
Slides: PDF

Date: Wednesday 11 October 2017 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Multi-Object Spectroscopy, Techniques and Challenges
Speaker, Affiliation: Dr. Alireza Molaeinezhad Postdoctoral researcher, School of Astronomy, IPM, Iranian National Observatory (INO)
Abstract: Multiplexed spectrographs on medium-class telescopes, with their large fields-of-view play a key role to the feature of observational astronomy and Cosmology. However, the scientific productivity of such complex instrumentation strongly depends on the availability of robust and reliable data-reduction/analysis methods and techniques. In this talk I will explain the main technical challenges in this field and introduce the dedicated IDL-based data reduction/calibration and analysis pipeline for the AF2/WYFFOS multi-fiber spectrograph. Then, I will go through the accuracy of sky subtraction, which is one of the most important aspect of the multi-fibre data reduction. As part of our ongoing effort to improve the reliability and precision of the sky subtraction in the dedicated IDL-based AF2+WYFFOS data reduction pipeline, we have applied the PCA approach to the sky estimation routines. The PCA algorithm can be used to find the relations between different skylight spectra and reconstruct a dedicated skylight spectra at position of each target fiber, based on the principle components of all available sky spectra. Our primary results show a significant improvement in the quality of the sky estimation, especially in longer wavelengths, where sky background is dominated by the emission lines originated from the OH radical.

Date: Monday 21 August 2017 Time: 14:00 hrs Place: Mayantigo building 6th floor meeting room
Title: A cosmic Bell test: Testing quantum mechanics with the help of cosmic random numbers
Speaker, Affiliation: Dominik Rauch, The Institute of Quantum Optics and Quantum Information Vienna, The Austrian Academy of Sciences.
Abstract: In their seminal paper from 1935, Einstein, Podolsky and Rosen state that quantum theory must be incomplete. They proof that without additional variables, the predictions of quantum mechanics, namely entanglement, contradict either locality or reality. Although this let to big discussions it was unclear of how to settle this matter until in 1964 John Stewart Bell found a way to experimentally investigate the question of local realism. Since 1972 many such Bell tests have been conducted, always in favour of quantum mechanics but always relying on assumptions, leading to so called "loopholes". We are planing a new Bell test on La Palma addressing the requirement that the measurement basis at each of the two measurement sites has to be chosen randomly. Our approach is to use the WHT and the TNG to produce random numbers from quasar light. The idea behind that has been published first in 2014 by Gallicchio et al.: if the received signal is old enough, causality can guarantee the impossibility that anything else, notably a potential local hidden variable, could influence the choice of the measurement basis. In a first experiment with milky way stars, we could show, that any influence would have been at least 600 years old: Handsteiner et al.:Cosmic Bell Test: Measurement Settings from Milky Way Stars, PRL 118, 060401.

Date: Friday 07 July 2017 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Update on HIPERCAM
Speaker, Affiliation: Professor Vik Dhillon; University of Sheffield and Instituto de Astrofisica de Canarias
Abstract: HiPERCAM is a high-speed, quintuple-beam CCD camera designed to study rapid brightness variations in the Universe. We intend to commission HiPERCAM on the WHT in Autumn 2017, and on the GTC in early 2018. In this talk, I shall provide a progress update on HiPERCAM, concentrating more on instrumentation aspects rather than scientific aspects.
Slides: PDF

Date: Tuesday 09 May 2017 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: The dawn of star formation: a local perspective
Speaker, Affiliation: Dr. Piercarlo Bonifacio; Laboratoire d'Etudes des Galaxies, Etoiles, Physique et Instrumentation GEPI, Observatoire de Paris, PSL Research University, CNRS, France
Abstract: At the end of the Dark Ages gravity began to make matter collapse around over-densities, resulting in the formation of the first stars, the Pop III. These stars are very important in the cosmological context, the most massive ones contributed ionizing photons that played a role in the reionization of the Universe and synthetised the first metals. We know that the formation mode of these first stars was different than the one operating today. The lack of metals implies it is difficult to cool a contracting cloud, which would argue for a preferential formation of massive or very massive stars. However from the theoretical point of view it is not yet possible to determine the initial mass function of the first stars. Simulations show that, even in the absence of metals, a collapsing cloud may fragment into smaller clouds giving rise to stars that span a range of masses, even sub-solar. Once the first metals begin to be shed in the clouds cooling becomes possible, either through atomic lines or through dust. It is likely that there is a transition from Pop III to "normal" Pop II star formation at some critical metallicity, however the precise value of this critical metallicity cannot be presently determined theoretically. In this seminar I will describe the observational efforts that our group is conducting in the local Universe, in order to derive as many constraints as possible on the nature of the Pop III stars. These include searches of the most metal-poor stars, and their chemical characterization. Both the metallicity distribution function and the chemical pattern of the most metal-poor stars contain precious information of the first stars.
Slides: PDF

Date: Thursday 27 April 2017 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Ultradeep Imaging of Galaxy Clusters
Speaker, Affiliation: Prof. Reyner Peletier, Kapteyn Institute Groningen
Abstract: In this talk I will discuss two ultradeep imaging surveys which I am leading. The first one is the WEAE Cluster survey, in which I, together with Alfonso Aguerri and Scott Trager, am determining photometric properties of dwarf galaxies in nearby X-ray selected clusters, for which later spectra will be obtained using WEAVE. The second one is the Fornax Deep Survey (FDS), a new, deep imaging survey of the Fornax Cluster, including the group of NGC 1316 (the Radio Galaxy Fornax A), observed with ESO’s VST by a European consortium with a strong contribution from INAFNaples (Italy) and Groningen. With data similar in depth to the NGVS survey of Virgo, we are studying many aspects of the formation of galaxies and the role of the environment, concentrating on dwarf galaxies, outer halos of massive galaxies, and globular cluster systems around galaxies. In this talk I will concentrate on studies of Ultra Diffuse Galaxies (UDGs) in Fornax, and on studies to characterise the dwarf population in nearby clusters. I will also discuss some aspects of follow-up surveys to study the objects found in the FDS in more detail.

Date: Tuesday 24 Jan 2017 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title:The EURONEAR Moving Object Detection System
Speaker, Affiliation: Denisa Copandean, PhD student, Technical University of Cluj-Napoca, Romania
Abstract: My PhD thesis in computing science applied to astronomy is based on a subject proposed by the European Near Earth Asteroids Research (EURONEAR) project. Part of this work, we are writing a prototype pipeline (in Python, Sextractor and IRAF) using two techniques aimed to detect near Earth asteroids (NEAs) but applicable to other moving objects. The first technique improves the classic "blink" algorithm to detect asteroids in series of a few (4-5) images, where the most difficult decisions will be assisted using computing visual methods and machine learning algorithms. The second technique will implement the newer "digital (or synthetic) tracking" method using series of many (dozens) of images, in the search of unknown objects moving in any direction and with proper motion. This is extremely computing intensive and can be applied to surveys using larger field small telescopes endowed with fast CMOS cameras. Thanks to a three month Erasmus+ stage which allowed me to work at the ING with Ovidiu Vaduvescu, the prototype implementing the blink technique has been written and is currently testing using INT-WFC archive images (including the first 9 NEA EURONEAR discoveries), while a mini-survey is planned soon to fully test this prototype.
Slides: PDF

Seminars in 2016

Date: Wednesday 02 Nov 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title:Regaining the FORS
Speaker - Affiliation: Henri Boffin - ESO Germany
Abstract: Transmission spectroscopy allows probing exoplanetary atmospheres, but such studies rely heavily on space-based or large ground-based facilities, as one needs to perform time-resolved, high signal-to-noise spectroscopy. Precision spectrophotometry with the ESO FORS2 instrument suffered from systematic errors that made quantitative observations of planetary transits impossible, the most likely cause being the Longitudinal Atmospheric Dispersion Compensator (LADC). We here present the project that was done to address this and show the level of improvement obtained, with several examples. It is our hope that FORS2 may become the instrument of choice for ground-based transmission spectroscopy of exoplanets.
Slides: PDF

Date: Thursday 20 Oct 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Analysing complex kinematics of distant starbursts with IFUs
Speaker - Affiliation: Dr. Guillermo Bosch, Instituto Astrofisico de La Plata (UNLP/Conicet), Argentina
Abstract: Strong starburst regions are located at distances that do not allow us to perform a detailed study of their stellar and nebular components. Most of our knowledge about these regions therefore relies on integrated properties derived from analysis of strong emission lines. High spectroscopic resolution echelle data provide detailed information that reveal complex behaviour of the ionized gas within each region, albeit lacking spatial resolution. In an attempt to disentangle the location of these components, we have obtained IFU spectra in excellent seeing conditions in a variety of starburst regions. I will describe some challenges that the analysis of IFU data present and some of their interesting results.

Date: Wednesday 5 Oct 2016 Time: 10:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Weak lensing measurements of high redshift clusters of galaxies using the HST
Speaker - Affiliation: Dr. Tim Schrabback, University of Bonn
Abstract: Weak gravitational lensing measurements directly constrain the projected mass distribution of foreground objects. Therefore they constitute a unique tool for investigations of the growth of structure in the Universe. As one application, weak gravitational lensing has been identified as the most direct technique for the redshift-dependent absolute calibration of observable-mass scaling relations of galaxy clusters. Improvements in this calibration are urgently needed in order to adequately extract cosmological information from deep cluster surveys. To measure weak lensing distortions the shapes of distant background galaxies need to be estimated robustly. For deep studies this requires high resolution imaging as currently best provided by the Hubble Space Telescope (HST). In this talk I will provide an overview of our HST study of distant massive galaxy clusters from the South Pole Telescope Sunyaev-Zel'dovich Survey. I will present results from our completed initial study of 13 clusters, highlight some of the key technical developments for systematic error control, and introduce our latest HST observations, which expand the sample and push to even higher redshifts. This also acts as a pilot study for similar future investigations with deep weak lensing data, as will be provided e.g. by ESA's Euclid mission.

Date: Wednesday 5 Oct 2016 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Clustering of Lyman-break galaxies at redshift z~3 in CFHTLenS
Speaker - Affiliation: PhD Student Beatriz Hernandez Martin, University of Bonn
Abstract: Dark matter can't be studied through direct observations but we can use the galaxies that trace its distribution in the sky. I will present the results of my master thesis on the study of dark matter halos at redshift z~3 by observing the clustering of Lyman-break galaxies (LBGs) in the Canada-France-Hawaii Lensing Survey (CFHTLenS). CFHTLenS is a deep survey with 5 bands which allows a color selection of the LBGs. A 3-parameter halo model is used to link the observed auto-correlation of LBGs to the underlying dark matter halos and obtain information on their average halo masses and mean occupation number. Obtaining the halo properties for different magnitude cuts helps us understand the evolution of the halos with luminosity and the relation with the kind of galaxies that populate them. More luminous galaxies should live in more massive halos and be more strongly clustered. The challenges and problems we encountered in the analysis will also be discussed.

Date: Thursday 29 Sep 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title:Galaxy formation in the first 3 Gyrs with wide field Lyman-alpha surveys
Speaker - Affiliation: Jorryt Matthee, PhD Student, Leiden University
Abstract: I will present our ongoing project to use the Lyman-alpha (Lya) emission line to study galaxy formation in the first 3 Gyr of cosmic time (z>3). At z>3, Lya is basically the only emission line used to spectroscopically confirm the distance of galaxies and it is used on its own to detect high-redshift galaxies with narrow-band surveys (such as our own at the INT) efficiently. Because of its sensitivity to neutral hydrogen, Lya is also a promising tool to study the epoch of reionization. I will focus on the need and benefits from wide field surveys, and highlight our major results. For example, we have found that the most luminous Lya emitters are more common than previously thought and that wide field (ground based) surveys can be extremely efficient in identifying bright galaxies at high redshift. Because of their brightness, these sources can be studied in great detail with instruments at the WHT, VLT, Keck, HST and ALMA. The brightest galaxy that we found, “COSMOS REDSHIFT 7” (CR7), is most spectacular, as it has spectroscopic evidence for a very hot source in an extremely low metallicity gas. This galaxy is currently our best laboratory to study the formation of stars and black holes in very metal poor, (almost) primordial gas.
Slides: PDF

Date: Friday 16 Sep 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: A Large Aperture Spectroscopic Survey Telescope
Speaker - Affiliation: Dr. Richard Ellis, European Southern Observatory (ESO) and University College London (UCL)
Abstract: I will report on the outcome of a ESO-sponsored Working Group to investigate the future of multi-object spectroscopy in the context of panoramic imaging surveys to be undertaken by LSST and Euclid. The report considers what is required beyond the capabilities of upcoming spectroscopic instruments such as 4MOST, WEAVE, PFS and DESI alongside powerful facilities such as the E-ELT and JWST. The report recommends consideration of a 10-12 meter class wide field survey telescope equipped with various multiplexed spectroscopic instruments. I will describe the scientific motivation for such a facility as well as the practicality of its eventual construction.

Date: Thursday 8 Sep 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Comparison of baffle and vanes in optical open truss telescope: stray light conontrol and airflow analysis
Speaker - Affiliation: Dr. Taoran Li, National Astronomical Observatories, Chinese Academy of Sciences (NAOC), ING student 2016
Abstract: Baffles and vanes are the most common methods in stray light control for optical telescopes. Unfortunately, when the air passes through the primary baffle, it will cause the disturbance (flow around circular cylinders) and influence the airflow above the primary mirror, blurring and twinkling the stars. The analysis about differences between baffle and vanes were performed. Raytrace simulations were performed by TracePro and fluid mechanics analysis by Ansys Fluent (CFD software). Stray light observations were made through a small open truss telescope. The analysis results indicate that, the primary baffle will improve the ability of stray light suppression of telescope, but have adverse effects on mirror cooling and air circulation. Meanwhile, the data from CFD will be used to calculate the mirror seeing. This method could be applied to any other telescopes. With the help of airflow and stray light analysis, the stray light control could be more reasonable.
Slides: PDF

Date: Tuesday 30 Aug 2016 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: New channels of single and binary evolution and nucleosynthesis
Speaker - Affiliation: Dr. Devika Kamath, Institute of Astronomy, University of Leuven, Belgium
Abstract: In this talk I will present the our work on an exotic group of evolved objects: post-AGB and post-RGB stars and the excellent constraints they provide for single and binary star evolution and nucleosynthesis. These objects have also revealed new evolutionary channels and AGB nucleosynthesis which is vital for understanding the complex chemical evolution of our Galaxy as well as external galaxies.
Slides: PDF

Date: Friday 4 Aug 2016 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Growth of massive galaxies through cosmic time
Speaker - Affiliation: Dr. Luis Peralta, ING student and IAC/ULL PhD graduate
Abstract: The discovery that massive galaxies are on average more compact in the early Universe has shown that size growth is a fundamental process in the cosmological evolution of massive galaxies. In my thesis I studied dynamical properties of these compact objects and inferred clues about the mechanism which drives size growth of massive galaxies. In the talk, we will start showing our work on the discrepancy between dynamical and stellar masses in massive compact early-type galaxies. Afterwards, we will derive velocity dispersions at z=1 with GTC/OSIRIS and discuss what size-evolution mechanisms are consistent with them. Finally we will address the question of which is the best environment for looking for relic galaxies, i.e. old galaxies which have not suffered the size evolution.

Date: Wednesday 16 Mar 2016 Time: 14:00 hrs Place: Mayantigo building 6th floor meeting room
Title: 67P and Rosetta - The story so far
Speaker - Affiliation: Dr. Alan Fitzsimmons - Astrophysics Research Centre, Queen's University Belfast, Northern Ireland
Abstract: Comet 67P has been the focus of intense study from before January 2014 when the ESA Rosetta spacecraft woke up from hibernation and commenced its approach. From arrival at the comet in August 2014, through perihelion in August 2015 to now, Rosetta and a wide sweep of ground-based facilities have been observing 67P, including most telescopes on La Palma through the award of an International Time Programme. This seminar will give an overview of the mission findings to date and include a look at preliminary results from La Palma and ING.

Date: Monday 11 Jan 2016 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: The HST GHOSTS Survey: the loneliest dwarf galaxy and stellar streams and Streams around NGC 891
Speaker - Affiliation: Dr. Benne W. Holwerda - Leiden Observatory
The HST GHOSTS Survey: the loneliest dwarf galaxy and stellar streams
I present a new faint dwarf galaxy, GHOSTS I, identified in HST/ACS data from the GHOSTS (Galaxy Halos, Outer disks, Substructure, Thick disk, and Star clusters) survey. It is detected in individual stars populate an approximately 1 mag range of its luminosity function (LF). Using synthetic color-magnitude diagrams (CMDs) to compare with the galaxy's CMD, we find that the colors and magnitudes of GHOSTS I's individual stars are most consistent with either RGB stars at 7.9 Mpc or He-burning and AGB stars at 12.2 Mpc. HI observations of this galaxy reveal several possible 21cm line peaks that could be consistent with either distance. The purpose of WHT/ISIS observations will be to break the degeneracy, critical to ascertain the HI gas mass and which stellar population is indeed present in this small satellite. Morphologically, GHOSTS I appears to be actively forming stars, so we tentatively classify it as a dwarf irregular (dIrr) galaxy, although future Hubble Space Telescope (HST) observations deep enough to resolve a larger magnitude range in its LF are required to make a more secure classification. GHOSTS I's absolute magnitude is MV~ -9.85+0.40-0.33 (assuming D=12.2Mpc), making it one of the least luminous dIrr galaxies known, and its metallicity is lower than [Fe/H] = -1.5 dex form the RGB slope. The half-light radius of GHOSTS I is 226 +/- 38 pc and its ellipticity is 0.47 +/- 0.07, similar to Milky Way and M31 dwarf satellites at comparable luminosity. There are no luminous massive galaxies or galaxy clusters within ~4Mpc from GHOSTS I that could be considered as its host, making it possibly the most isolated dwarf galaxy in the local Universe.
Streams around NGC 891
In HST GHOSTS data, I have identified two sections of the stellar streams surrounding this canonical edge-on spiral galaxy, at ~600'' and ~300'' from the nucleus on the major and minor axes respectively. The stellar stream does not contain young stars (less than 1Gyr), with a metallicity of [Fe/H] ~ -0.7, similar to earlier estimates for the streams surrounding NGC 891. I argue that the spatial overlap between the stellar stream in the HST observations and a known counter-rotating Hi complex is likely a coincidence (or a projection effect) but the morphology of all the extra-planar HI and the streams in general does suggest a common origin. The color-magnitude diagram of the stellar population reveals no recent (massive) star-formation in this counter-rotating HI gas complex. The metallicity suggests a MV = -14 dwarf galaxy progenitor for this stream and –if all the counter-rotating HI gas is indeed part of this accretion event– likely a late-type dwarf galaxy. If both HI and stellar streams originate from a single system, the stellar mass (~ 108 Ms ) to gas (several 106 Ms ) ratio suggests that most of the accreted gas has already been assimilated by NGC 891 or its halo.

Date: Friday 8 Jan 2016 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: The new Hong-Kong/AAO/Strasbourg multi-wavelength and spectroscopic PNe database: HASH
Speaker - Affiliation: Prof. Quentin A Parker, Ivan Bojicic and David J. Frew, The Univ of Hong Kong
Abstract: We are in a golden age of PN discovery. This advent of high sensitivity, wide-field, narrow-band surveys of the Galactic plane undertaken on the UKST in Australia, the Isaac Newton telescope on La Palma and now the VST in Chile have facilitated this process. These telescopes and their H-alpha surveys have provided significant Planetary Nebulae (PNe) discoveries that have more than doubled the totals accumulated by all telescopes over the previous 250 years. Importantly, these PNe are not the just the same as those found in previous catalogues. Most new PNe are more obscured, evolved and of lower surface brightness than previous compilations while others are faint but compact and more distant. This has required an extensive and time-consuming programme of spectroscopic confirmation on a variety of 2m and 4m telescopes that is now largely complete. The scope of any future large-scale PNe studies, particularly those of a statistical nature or undertaken to understand true PNe diversity and evolution should now reflect this fresh PN population landscape of the combined sample of ~3500 Galactic PNe now available. Such studies should take into account these recent major discoveries and the massive, high sensitivity, high resolution, multi-wavelength imaging surveys now available across much of the electromagnetic spectrum. Following this motivation we provide, for the first time, an accessible, reliable, on-line "one-stop" SQL database for essential, up-to date information for all known Galactic PN. We have attempted to: i) Reliably remove the many PN mimics/false ID's that have biased previous compilations and subsequent studies; ii) Provide accurate, updated positions, sizes, morphologies, radial velocities, fluxes, multi-wavelength imagery and spectroscopy; iii) Link to CDS/Vizier and hence provide archival history for each object; iv) Provide an interface to sift, select, browse, collate, investigate, download and visualise the complete currently known Galactic PNe diaspora and v) provide the community with the most complete and reliable data with which to undertake new science.
Slides: PDF

Date: Thursday 7 Jan 2016 Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: AstroWise - Data federations for large imaging surveys
Speaker - Affiliation: Prof. Dr. Edwin Valentijn, Kapteyn Astronomical Institute, Department of Astronomy, University of Groningen, The Netherlands
Abstract: Astronomical wide field optical imaging surveys play an important role as front runners in modern IT networks and data bases. The AstroWise information system is  operational for  the production of the results of a number astronomical survey programmes with OmegaCAM@VST and MUSE@VLT. In different forms it also hosts, the Lofar radiotelescope, ING, WFI 2.2m, life science projects and business applications. I will discuss the common "data federation" aspects of these projects, and the data federation aspects of the Euclid Archive System which will serve over 100 institutes and over 1000 researchers in Europe.

Seminars in 2015

Past Seminars

Date: Friday 04 Dec 2015 Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Constraints to the magnetospheric properties of T~Tauri stars
Speaker - Affiliation: Dr. Fatima Lopez, ING.
Abstract: T~Tauri stars (TTS) are young and low-mass pre-main sequence stars. They have a surrounding disk as well as strong and complex magnetic fields. The disk is truncated near the corrotation radius due to its interaction with the stellar magnetic field. The material in the inner part of the disk is ionized by the stellar radiation and channelled through the magnetic field lines. The gas from the disk is accelerated to almost free-fall velocity before it reaches the stellar surface forming an accretion shock. The ultraviolet luminosities of TTS exceed by 1-2 orders of magnitude those observed in main sequence stars of the same spectral types. This excess is associated with the accretion process that transports material onto the stellar surface enhancing the flux radiated by magnetospheric/atmospheric tracers. The energy produced in the atmosphere and magnetosphere is released mainly in the ultraviolet range. The study of TTS provides some important clues about young stars, planetary system formation and their early evolution. The spectra of TTS show peculiar features, mainly in the ultraviolet range. Most of the TTS emission is produced in a region of the magnetosphere with temperatures of about 10000~K. In this talk I will speak about the work developed in my PhD thesis, in which I analysed ultraviolet spectral lines formed in regions with those temperatures, (C~II], Fe~II], Si~II] and Mg~II). The study of these lines allowed me to determine some constraints to the magnetosphere properties in TTS.

Date: Monday 16 November Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Cosmic butterflies: the product of tempestuous stellar marriages
Speaker - Affiliation: Dr. David Jones, IAC, Spain.
Abstract: Planetary nebulae are some of the most strikingly beautiful astrophysical phenomena known, gracing many a glossy-paged, coffee-table book and earning them the nickname "cosmic butterflies".  Classical stellar evolutionary theory states that all intermediate mass stars should produce a planetary nebula, forming as the star leaves the Asymptotic Giant Branch and evolves towards the white dwarf phase.  While it remains the standard for astronomy textbooks, this paradigm has gradually become less and less accepted by the planetary nebula community. As such, it is now clear that a significant fraction of planetary nebulae originate from a binary evolutionary pathway, with some theories even going as far as to say that binarity may be a prerequisite for all but the most massive stars to form a planetary nebula.  However, the full importance of binarity on the formation and evolution of planetary nebulae is far from understood, with large observational and theoretical challenges ahead.  In this seminar, I will begin by outlining some fundamentals of close binary evolution and how they relate to the formation of planetary nebulae, before going on to describe our current observational efforts to resolve the open questions of the field.  I will highlight a few key systems which bear great importance for our current understanding, including the super-Chandrasekhar mass, double-degenerate at the heart of the planetary nebula Hen 2-428 - the strongest supernova type Ia candidate known to-dat, and a discovery (made entirely with telescopes at the ORM, including the INT, Mercator and GTC) which demonstrates the wide-reaching importance of this investigation.
Slides: PDF

Date: Thursday 8 January Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: A gentle introduction to astronomical polarimetry
Speaker - Affiliation: Dr. Stefano Bagnulo, Armagh Observatory, UK.
Abstract: Most of astronomy is based on measurements of the intensity of the radiation. Little attention is usually paid to HOW radiation propagates, i.e., whether the light that we observe is "polarised" along a preferred direction. Polarisation originates whenever any kind of anisotropy occurs in the emitting source, or between the source and the observer, for instance scattering by matter, presence of collimated beams of particles, presence of a magnetic field. In this talk I will present some applications of polarimetry in common life and in astronomy, and in particular I will explain how polarimetry may may be used to detect stellar magnetic fields, to characterise the surface of and the atmospheres of the bodies our and other solar systems, and help us to find extra-terrestrial life.

Seminars in 2014

Date: 17 Dec 2014 (Wed) Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: HiPERCAM: A high-speed camera for the study of rapid variability in the Universe.
Speaker - Affiliation: Prof. Vik Dhillon, Sheffield University, UK.
Abstract: I shall describe the scientific motivation and design of HiPERCAM, a five-channel, high-speed optical CCD camera. The instrument, which has been funded by a 3.5 Meuro European Research Council Advanced Grant, is currently under construction at Sheffield/Warwick/Durham/UKATC, and we hope to commission it on the WHT in early 2017.

Date: 24 Nov 2014 (Mon) Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Star Clusters at IA and NAO Rozhen
Speaker - Affiliation: Grigor Nikolov - Institute of Astronomy with National Astronomical Observatory, Bulgarian Academy of Sciences.
Abstract: In this talk I will briefly present the research on star clusters done at IA&NAO Rozhen. Our small group is observing galactic clusters and also using archival space telescope images of our neighbour galaxy, the LMC.
Slides: PDF

Date: 24 Nov 2014 (Mon) Time: 14:30 hrs Place: Mayantigo building 6th floor meeting room
Title: The Bulgarian Institute of Astronomy and the National Astronomical Observatory at Rozhen.
Speaker - Affiliation: Mirela Napetova - Institute of Astronomy with National Astronomical Observatory, Bulgarian Academy of Sciences.
Abstract: I will briefly introduce you to our home institution, the main work areas of our colleagues and the reasearch facilities available, including the National Astronomical Observatory at Rozhen.
Slides: PDF

Date: 11 July 2014 (Fri) Time: 15:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Stellar and planetary remnants in large area surveys
Speaker - Affiliation: Nicola Pietro Gentile Fusillo - University of Warwick & ING
Abstract: With over 1000 exoplanets confirmed to date the research focus is shifting from discovery to characterization. White dwarfs are the final evolutionary stage of stars with between 8 M☉ and 0.8 M☉. This mass range included almost all known planet hosts including our Sun and it is therefore very likely that white dwarfs could have one day hosted and may still host planetary systems. Because of the very high surface gravity of white dwarfs, any heavy elements sinks to deeper layers of the atmospheres living an outer and visible layer purely composed of the lightest elements i.e. H or He. Therefore the existence of white dwarfs which show traces of heavy elements in their atmosphere can only be explained as ongoing accretion from surrounding sources. The widely accepted theory today is that such white dwarfs are accreting heavy rocky material from a circumstellar disk formed from the tidal disruption of remnants of planetary systems. IR observations of the white dwarfs can confirm the presence of such discs and accurate atmospheric analysis can be used to estimate the composition and mass of the accreted body. Currently metal polluted white dwarfs are the only venue available to determine the composition of rocky planetary systems and we are just starting to exploit their potential in this field. However these objects are both rare and difficult to find. Therefore a systematic search for these systems will require a large reliable catalogue of white dwarfs. In this presentation I will discuss the work we have done in developing a selection method for white dwarfs and the subsequent application of this method in our search for metal polluted white dwarfs.

Date: 19 June 2014 (Thu) Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Search for hidden turbulent gas through interstellar scintillation
Speaker - Affiliation: Prof. Dr. Marc Moniez - Laboratoire de l'Accelerateur Lineaire, IN2P3-CNRS, France
Abstract: We propose a new way to search for (hidden) cool molecular hydrogen H2 in the Galaxy through diffractive and refractive effects: Stars twinkle because their light crosses the atmosphere. The same phenomenon is expected on a longer time scale when the light of a remote star crosses an interstellar turbulent molecular cloud, but it has never been observed at optical wavelengths. Our simulations and test observations show that in favorable cases, the light of a background star can be subject to stochastic fluctuations on the order of a few percent at a characteristic time scale of a few minutes. We searched for scintillation caused by molecular gas within visible dark nebulae as well as by hypothetical halo clumpuscules of cool molecular hydrogen (H2-He) with the ESO-NTT telescope. Within a few thousands of densely sampled light-curves, we found one candidate that shows variabilities compatible with a strong scintillation effect through a turbulent structure of the B68 nebula. Furthermore, since no candidate has been found toward the SMC, we were also able to establish upper limits on the contribution of gas clumpuscules to the Galactic halo mass. I will discuss the perspectives of synchronized observations with two large distant telescopes, to observe the time decorrelation between the light curves, an undisputable signature of the scintillation process. I will then show that a few nights of observation using the so-called "movie-mode" of LSST should allow one to significantly constrain the last unknown baryonic contribution to the Galactic mass.
Slides: PDF

Date: 10 June 2014 (Tue) Time: 11:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Planck cosmological results overview, and how ground-based telescopes can help
Speaker - Affiliation: Dr. Herve Dole, Deputy Director - Institut d'Astrophysique Spatiale, Orsay, France (Univ. Paris Sud, CNRS, IUF) member of the Planck collaboration
Abstract: Planck, the European Space Agency's science cornerstone missions launched in 2009 dedicated to cosmology, has measured the relic radiation from the Big Bang (the Cosmic Microwave Background, or CMB) with improved sensitivity and resolution, in order to test theories on the birth and evolution of the Universe and its large-scale content. In spring 2013, we released the first cosmological results, which I will review. In particular, thanks to the best ever measured map of the CMB, we can improve our knowledge about the age, content and evolution of our Universe, as well as, for the first time, the very first moments (inflation) or the growth of structures. I will also mention the technological challenge (the HFI instrument is cooled at 0.1K in space) that made this mission a success. In the 2nd half, I will focus on some selected topics about the "foregrounds", mainly galaxies (including infrared background, high-redshift sources followed-up by Herschel), but also SZ clusters.

Date: 19 May 2014 (Mon) Time: 10:00 hrs Place: Mayantigo building 6th floor meeting room
Title: CARMENES: the Calar Alto exoplanet hunter
Speaker - Affiliation: Dr. Jose A. Caballero - Centro de Astrobiologia, CSIC, Madrid
Abstract: CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument being built for the 3.5m telescope at the Calar Alto Observatory by a consortium of German and Spanish institutions. It consists of two separated spectrographs covering the wavelength ranges from 0.5 to 1.0 microns and from 1.0 to 1.7 microns with spectral resolutions R = 82,000, each of which shall perform high-accuracy radial-velocity measurements (~1 m/s) with long-term stability. The fundamental science objective of CARMENES is to carry out a survey of ~300 late-type main-sequence stars with the goal of detecting low-mass planets in their habitable zones. We aim at being able to detect 2 MEarth planets in the habitable zone of M5V stars. The CARMENES first light is expected to occur in Summer 2015. CARMENES website.
Slides: PDF

Date: 09 May 2014 (Fri) Time: 11:30 hrs Place: Mayantigo building 6th floor meeting room
Title: The Terra Hunting Experiment @ Isaac Newton Telescope project
Speaker - Affiliation: Prof. Didier Queloz - Cavendish Laboratory (Cambridge, UK)
Abstract: We are still far from having a comprehensive view of the full diversity of planetary systems predicted by models of planet formation and have not yet detected any "Earth Twin", making it difficult to set our Solar System in context. Part of the reason for this is an unforeseen contribution to the noise budget arising from magnetic and convective effects in the stellar atmosphere. Stellar activity has become the main limiting factor, making difficult the detection of planets like Earth by either transit or Doppler survey programs. This additional noise structure, intrinsic to the astrophysical nature of stars, slows down progress and requires new strategies to be developed to circumvent this limitation. The astrophysical noise structure is amplified by the window function of the observation and produces a forest of aliases, which prevent us from digging out unambiguous small signals. To address this, we are proposing a "Terra Hunting Experiment" to be performed using a close-copy of the HARPS spectrograph installed on the 2.5m Isaac Newton Telescope (INT) in La Palma and dedicated for this program. The survey, operating over a minimum of 5 years, will target the nearest, brightest, solar-like stars.

Date:05 March 2014 (Wed) Time: 10:00 hrs Place: Mayantigo building 6th floor meeting room
Title: Protoclusters in formation: cluster formation, star formation and red sequence formation
Speaker - Affiliation: Elizabeth Cooke - University of Nottingham, UK
Abstract: Studying galaxy clusters throughout the process of formation is essential to our understanding of the physics underlying cluster galaxy evolution. Finding high redshift (proto)clusters, however, is difficult and they have proved elusive in large field surveys. One of the most successful methods in recent years has been to use high redshift radio loud AGN as beacons for overdensities and (proto)clusters of galaxies in the distant universe. Recently, targeting one such radio galaxy, I have confirmed the existence of a protocluster at z=2.5. Using multi-wavelength data from the optical through to MIPS and Herschel IR data, I will present my results on the star-forming properties of the protocluster galaxies compared to those of a field sample and examine the SFR-mass relation as a function of environment at z>2. Finally, I will present a preview of my ongoing work studying of the formation of the cluster red sequence with the Clusters Around Radio-Loud AGN (CARLA) survey. The bright end of the red sequence is firmly in place by z~1 and, in the densest environments, individual red sequences have been found out to z~2. Using a large sample of galaxy clusters and protoclusters, I am using ACAM i' band imaging in conjunction with Spitzer data to examine the build-up of the cluster red sequence across 1.3.
Slides: PDF

Seminars in 2013

Date: 05 Nov (Tue) Time: 11:30 Place: 6th floor meeting room, Mayantigo building
Title: Data reduction and archiving for massive spectroscopic surveys
Speaker (Affiliation): Dr. Adam Bolton, University of Utah (USA)
Slides: PDF

Date: 25 Oct (Fri) Time: 10:30 Place: 6th floor meeting room, Mayantigo building
Title: The Second Data Release of the INT/WFC Photometric H-alpha Survey (IPHAS)
Speaker (Affiliation): Dr. Geert Barentsen, University of Hertfordshire, UK
Abstract: IPHAS is a 180x10 square-degree survey of the northern Galactic Plane, collecting r, i and H-alpha photometry for more than 100 million stars down to point source magnitudes of ~21. The original motivation for undertaking this large-scale programme of observation - spanning almost a decade, and using more than 300 nights at the Isaac Newton Telescope (INT) - was to provide the digital update to the photographic northern Ha surveys of the mid-twentieth century. By increasing the sensitivity with respect to these previous surveys by ~1000 (~7 magnitudes), IPHAS has enabled the discovery of larger, deeper, more statistically-robust samples of Galactic emission line objects which inform our understanding of early and late stages of stellar evolution. Moreover, the survey's unique (r-Ha) colour offers a rough extinction-free proxy for intrinsic colour, which has opened the door to a wide range of Galactic science applications, including the mapping of extinction across the Plane in three dimensions. The first release of IPHAS data, covering roughly half the survey footprint, was made in 2008. During this talk I will present the next data release, which takes the coverage up to over 90 percent of the survey area. I will describe the quality control and data processing steps which have been applied to arrive at a new, homogeneously calibrated, source catalogue containing more than 100 million unique stars. Finally, I will explain the challenges which remain to bring this legacy survey to its final completion.
Slides: PDF

Date: 24 Sep (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: The Next Generation Transit Survey
Speaker (Affiliation): James McCormac, ING
Abstract: The Next Generation Transit Survey (NGTS) is a new wide-feld transiting exoplanet survey aimed at discovering Neptune and super-Earth size exoplanets around bright (V < 13) stars in the solar neighbourhood. NGTS is currently under construction at ESO's Paranal observatory, Chile and consists of an array of 12 robotically operated telescopes observing in the 600-900 nm band; hence maximising the sensitivity to small but bright K and M dwarf stars. Observing K and early M type stars theoretically permits the detection of smaller transit-ing exoplanets as the radius of the host star is reduced compared to solar-type stars. Simulations have shown that NGTS will survey more than ve times the number of stars with V < 13 than Kepler and will therefore provide the bright-est targets for characterisation with existing and future instrumentation (VLT, E-ELT and JWST). Many recent discoveries of planetary systems harbouring Neptune-mass planets and super-Earths clearly indicate that low-mass planets around solar-type stars are very common. Paranal boasts exceptional photo-metric conditions and a low atmospheric water vapour content for a signicant fraction of the year, which is essential for NGTS to perform photometry at the required millimagnitude level or better. In 2009/10, a prototype for NGTS was tested on La Palma, proving that such a system can meet our goals of essentially white noise limited photometry of bright stars. Several improvements in the design of NGTS resulted from the prototyping phase (e.g. requirements for baing and autoguiding) and have now been integrated into the facility at the ground level. The NGTS project is made up of partners from the University of Warwick, University of Leicester, Observatoire de Geneve, DLR Berlin, Queen's University Belfast and the Universidad Catolica de Chile. NGTS builds on the experience of the SuperWASP project, which, for many years, has lead the ground-based detection of transiting exoplanets.
Slides: PDF

Date: 30 Aug (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: What the occult can do for you
Speaker (Affiliation): Benne Holwerda, European Space Agency (ESA)
Abstract: Occulting galaxy pairs i.e. the serendipitous overlap of two galaxies, can be used to detect and map interstellar dust in galaxies, assuming both galaxies are symmetric.  The GalaxyZoo identified some 2000 occulting pairs. Differential photometry reveals  the amount of dust while long-slit or integral field unit observations directly measure the extinction curve through the foreground galaxy. I will discuss our ongoing follow-up efforts on the occulting pairs identified by the GalaxyZoo volunteers (GALEX, HST, WHT, WYIN etc) and future uses for the resulting measures of dust extinction (e.g. as a prior in SNIa measurements).
Slides: PDF

Date: 13 Aug (Tue) Time: 10:00 Place: 6th floor meeting room, Mayantigo building
Title: Mind the gap: transitional disks and their host stars
Speaker (Affiliation): Nienke van der Marel (Leiden Observatory, The Netherlands)
Abstract: Planet formation and clearing of protoplanetary disks is one of the long standing problems in disk evolution theory. The best test of clearing scenarios is observing systems that are most likely to be actively forming planets: the transitional disks with large inner dust cavities. However, other mechanisms during this phase of disk evolution may also carve out inner holes in disks. We have identified 170 new transition disk candidates, tripling the known sample. Using optical and near infrared spectroscopy obtained with the WHT, we can derive the stellar parameters for the targets in this sample. These parameters allow further analysis of the SED (Spectral Energy Distribution), assessing the hole size and disk dissipation mechanisms. Eventually, further analysis of the combined gas and dust distribution in these disks using the Atacama Large Millimeter Array will provide better clues to the start of planet formation.
Slides: PDF

Date: 04 July (Thu) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Star forming sites around HII regions and supernova remnants
Speaker (Affiliation): Dr. Sergio A. Paron (Instituto de Astronomia y Fisica del Espacio (IAFE) - Buenos Aires, Argentina)
Abstract: Nowadays it is well known that massive stars in our Galaxy are born predominantly within the dense cores of giant molecular clouds. They usually form and evolve in clusters,hence it is expected to observe several HII regions in different evolutionary stages and probably also supernova remnants (SNRs) in a same Galactic neighbourhood. Moreover, it is usually observed large amounts of molecular gas in the surroundings of HII regions and SNRs. The shock and ionization fronts from these objects, which compress and sweep up the gas, can trigger the formation of a new generation of massive stars. In this talk I will show some results from our multiwavelenth studies towards several star forming sites around both SNRs and HII regions.

Date: 17 Jun (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: How to submit a successful observing proposal
Speaker (Affiliation): Dr. Marc Balcells (ING Director and IAC, Spain)
Abstract: The talk will cover recommendations for writing observing proposals, including: organising preparatory work; giving your proposal a good structure; clues on a good title and a good abstract; recommendations on figures and figure captions; recommendations on latex; and suggestions on how to learn from proposals that did not get time.
Slides: PDF

Date: 10 Jun (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Ultracompact AM CVn binaries and their progenitors
Speaker (Affiliation): Drd. Thomas Kupfer (Department of Astrophysics, Radboud University Nijmegen, The Netherlands)
Abstract: AM CVn systems are a small group of mass transferring ultracompact binaries with orbital periods between 5.4 and 65 min. They consist of a white dwarf (WD) primary, and a WD, or semi-degenerated helium star secondary. AM CVn systems are important as strong low-frequency Galactic gravitational wave sources and will act as verification sources for upcoming space based gravitational wave detectors like eLISA/NGO. They might also be the source population of the proposed Ia supernovae. An open question is still at which number WD donors or helium star donors contribute to the population of AM CVn systems. We have started a project to search for AM CVn binaries and compact binaries which might evolve into AM CVn type binaries. I will report on the discovery of an interesting progenitor system which is a good candidate to explode as an underluminous supernova and present a project to find these interesting compact binaries using the UVEX database. I will also present the results of phase-resolved spectroscopy of four AM CVn systems obtained with the William Herschel Telescope and the Gran Telescopio de Canaries (GTC). We measured orbital periods and used flux ratios of different helium lines to estimate the temperature of the accretion disc and the bright spot where the accretion stream hits the accretion disc.
Slides: PDF

Date: 17 May (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Evolution in galaxy cluster cores since half way back to the big bang
Speaker (Affiliation): Dr. Claire Burke (Astrophysics Research Institute, Liverpool John Moores University, UK)
Abstract: Galaxy clusters are the densest regions of matter in the Universe and their cores were formed from the first density peaks to collapse after the big bang, as such they are ideal regions for studying the buildup of large scale structure in the Universe. The cores of galaxy clusters are usually dominated by a massive brightest cluster galaxy (BCG). Sitting at the centre of mass of galaxy clusters, BCGs are the most massive, most luminous galaxies observed. Studies of the mass assembly of BCGs provide a major challenge for current cosmological models as they are observed to have assembled the majority of their present day mass by z>~1, equivalent to half way back to the big bang. This indicates an assembly which is much more rapid than current models predict. BCGs are surrounded by diffuse, faint intracluster light (ICL) which pervades the whole cluster and extends beyond its visible limits. Whilst faint, the ICL contains a large fraction of the stellar mass of nearby clusters (as much as 80%), however its origins and assembly history are unknown. I will present our recent observational studies of the assembly and evolution of BCGs and the ICL since half way back to the big bang. Our results show very little evolution the for half-light radii of BCGs, highlighting them as a population distinct from normal or field ellipticals; however we find that BCGs should undergo a large number of mergers, both major and minor over this time. We also find a rapid and large growth in the ICL over the same time. The large number of expected mergers onto BCGs their along with the observed lack of growth in mass and radius indicates that the majority of the stellar mass from mergers must end up in the ICL rather than centrally on the BCG. These results point to a rapid early assembly of massive galaxies in clusters followed by passive evolution, with interactions between galaxies in clusters mainly occurring by stripping to build up the ICL at later times.

Date: 14 February (Thu) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Gamma Ray Burst Polarimetry with the Liverpool Telescope
Speaker (Affiliation): Drd. Doug Arnold (Liverpool John Moores University and ING student)
Abstract: Gamma Ray Bursts (GRBs) are the most high energy events in the Universe since the big bang. First discovered in the 1960s it was not until this century that GRBs could be reliably followed up at other wavelengths by ground based facilities. In the SWIFT era, ground based follow-up from robotic telescopes, such as the Liverpool Telescope, enable early time (less than 5 minutes post burst) observations which aid us in understanding the progenitors of these events. Early time polarimetry has been an exceptionally valuable tool in confirming models of emission within gamma ray bursts. The talk will present an overview of GRB theory, detail the Liverpool Telescope capabilities and present new results of the polarimetry of six bursts.
Slides: PDF

Date: 25 January (Fri) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: A 3D view of the nova remnant of GK Per
Speaker (Affiliation): Dr. Tiina Liimets (Tartu Observatory, Estonia)
Abstract: Due to the high expansion speed, the apparent growth of the nearby nova remnant GK Per can be easily resolved from ground-based optical imagery on a timescale of months. For that reason, starting on 2004 we embarked in a program of frequent imaging monitoring of the expansion of the GK Per remnant with the Isaac Newton Telescope and Nordic Optical Telescope. The expansion in the plane of the sky coupled with Doppler shift velocities allowed us to obtain a unique 3D view of the ejecta and carry out a detailed kinematical and dynamical study. The main results of our work are discussed in this presented.

Date: 24 January (Thu) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Does every large spiral galaxy contain a classical bulge?
Speaker (Affiliation): Prof. Dr. Reynier Peletier (Chair of Kapteyn Instituut Groningen, Netherlands)
Abstract: It has become clear in recent years that bulges of galaxies come in two flavours: classical bulges, that are very similar to small elliptical galaxies, and so-called pseudobulges, that are very similar to disks. In this talk I try to show that it is possible that spiral galaxies do not contain a classical bulge or a pseudobulge, but that they always have a classical bulge, together with possibly a pseudobulge. This has strong consequences about the build-up of galaxies. In the end, I will also talk about scientific interests in the Netherlands for the WHT and INT.

Seminars in 2012

Date: 11 December (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: The EURONEAR project and its successful collaboration with students and amateurs
Speaker (Affiliation): Dr. Ovidiu Vaduvescu, Isaac Newton Group, IAC and IMCCE associated
Abstract: I will present the European Near Asteroid Research (EURONEAR), a project dedicated to Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). Founded in 2006, EURONEAR currently joins 17 collaborating nodes and more than 50 astronomers from eight countries interested in the orbital properties (via astrometry) and physical properties of NEAs and PHAs (using photometry, spectroscopy and polarimetry). Following a brief overview about NEAs and their possible risk posed to Earth, I will list 10 projects/papers completed mostly in collaboration with students and amateur astronomers, including few other projects related to EURONEAR. These papers include data from 14 telescopes (0.3-4m) accessed by the EURONEAR network in Chile, La Palma, France, Germany and Romania, in addition with data mining of wide field archived images from 2-8m telescopes. The future of EURONEAR will be finally resumed, including the need of at least one 2m class telescope dedicated to NEA work.
Slides: PDF

Date: 26 November (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: WEAVE: The next generation wide-field spectroscopy facility for the WHT
Speaker (Affiliation): Prof. Dr. Gavin Dalton, STFC-RAL, WEAVE PI, United Kingdom
Abstract: I will describe the major scientific motivation and outline design concept for a new 2 degree field, 1000 fibre multi-object spectroscopy facility for the WHT. WEAVE is expected to be completed by early 2017 and will be capable of addressing a wide range of Galactic and extra-Galactic goals, covering the redial velocity follow-up to the full depth of the Gaia astrometric catalogue, stellar abundances and chemical labelling in the Galactic halo, galaxy evolution from integral field studies and from the identification of the LOFAR source population, and Cosmology. The instrument is complex, but not necessarily challenging, and will provide a major resource for the whole ING community for the next decade. I will try to include some details of the operational implications for the telescope.

Date: 19 November (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Core-collapse supernovae: progenitors and dust production
Speaker (Affiliation): Dr. Rubina Kotak, Queen's University, Belfast, Northern Ireland, United Kingdom
Abstract: Recent years have witnessed a flurry of studies that have emphasised the important role that dust plays in our understanding of the near and distant Universe. The short time-scales required for dust enrichment make core-collapse supernovae rather natural candidates for dust producers in the early Universe. Yet, direct evidence that grains condense in such supernovae is rather sparse. Here, I will discuss recent results, and attempt to put the role of core-collapse supernovae as dust producers into perspective. I will also review what is currently known about the progenitors of core-collapse supernovae, and how this ties into the observed properties of core-collapse supernovae, including their ability to produce dust at relatively early epochs in their evolution. I will discuss how such studies might evolve in the light of current and future surveys / facilities.

Date: 21 September (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Large-scale Galactic massive star surveys
Speaker (Affiliation): Dr. Jesus Maiz Apellaniz, Instituto de Astrofisica de Andalucia - CSIC
Abstract: In the last decades, large-scale surveys have become a dominant mode of doing astronomical research, as e.g. 2MASS, SDSS, or Hipparcos evidence. In this talk I will describe several ongoing spectroscopic and imaging massive-star surveys in the Galaxy, including three that are being carried out from La Palma. Such surveys are interesting because of the enormous impact that massive stars have on galactic evolution in terms of radiative, kinetic energy, and chemical evolution effects. A large effort is needed to do them because studying massive stars is complicated by their scarcity, extinction, spatial distribution, and a nasty habit of hating loneliness. Our final goal is to study at least 5% of the O stars in the Milky Way in order to build for the first time a high-quality complete database of massive stars in the solar neighborhood. I will discuss our ongoing studies on the multiplicity, spatial distribution, and IMF of the massive stars in the solar neighborhood and of the imprint of the ISM on their colors and spectra.

Date: 14 September (Fri) Time: 10:00 Place: 6th floor meeting room, Mayantigo building
Title: Red supergiants in the Milky Way: Massive clusters and supernova progenitors
Speaker (Affiliation): Prof. Ignacio Negueruela, Universidad de Alicante
Abstract: Red supergiants represent a decisive phase in the evolution of high-mass stars. The recent identification of several supernova progenitors in nearby galaxies has shown that most supernova explosions are type II plateau, occurring in red supergiants. Surprisingly, these observations suggest that most explosions happen in stars with 7 to 10 Msun, unexpectedly low values. In contrast, the population of well-characterised red supergiants in the Milky Way is dominated by rather more massive objects, typically with >=15 Msun, in sharp contrast with expectations based on the shape of the IMF. In this seminar, I will present the first results of our search for red supergiants in regions of high reddening, which has led to the discovery of several massive clusters near the base of the Scutum arm. I will also present preliminary results of our ongoing observational campaign aimed at providing accurate parameters for a sample of open clusters with ages in the 30-60 Myr range, containing sizeable numbers of K-type supergiants.

Date: 13 August (Mon) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: The early Universe just around the corner: Fornax dSph
Speaker (Affiliation): Dr. Andrés del Pino Molina, Instituto de Astrofísica de Canarias, Spain
Abstract: We present the full Star Formation History as a function of radius of the Fornax dSph galaxy. We also present the preliminary results of the spatial distribution of the stellar populations. We found significant differences in the populations as a function of the galactocentric radius, which may be the result from interactions between Fornax and other systems. The implications of the obtained results on the dwarf spheroidal galaxies evolution are also discussed. This study is based on FORS1@VLT photometry as deep as I ~24.5 and the IAC-star, IAC-pop and MinnIAC codes.
Slides: PDF

Date: 31 July (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Nuclear stellar disks as tracers of galaxy merging history
Speaker (Affiliation): Hugo Ledo, Isaac Newton Group of Telescopes and University of Hertfordshire
Abstract: The current hierarchical paradigm for galaxy formation predicts early-type galaxies to have been formed through the merging of galaxies of similar mass. During this process, old nuclear stellar disks (NSD), if present, will be destroyed and new ones can be formed. We can therefore use the age of the stars in the nuclear disks to constrain the look-back time since the last major merging event. We present the first NSD census together with a study of some of the disks' properties and a new technique to deal with the degeneracy between age and mass to better constrain the age of disk stellar populations which we have applied to the case of NGC4458.

Date: 27 July (Fri) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: Characterizing exoplanet atmospheres with ground-based telescopes
Speaker (Affiliation): Dr. Ernst De Mooij - Department of Astonomy and Astrophysics, University of Toronto, Canada
Abstract: In the 16 years since the discovery of the first planet outside our solar-system, the field of exoplanet research has made a lot of progress. Not only has the number of known exoplanets increased to almost 800, it has also become possible to detect the atmospheres for several dozen of these exoplanets. For transiting planets we can study their atmosphere both in transmission (during the transit), as well as in emission/reflection during the secondary eclipse (when the planet passes behind the star). Until a few years ago, the characterization of exoplanet atmospheres was only possible using space-based telescopes. However, I will show that ground-based telescopes can be used to reach the high precision required to detect the atmospheric signatures and can provide complementary information to space-based observations. In addition, I will also discuss some of the challenges we encounter when doing these observations.

Date: 23 July (Mon) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: High-redshift proto-cluster radio galaxies and the search for molecules in the early Universe
Speaker (Affiliation): Dr. Bjorn Emonts - CSIRO Astronomy and Space Science / ATNF, Australia
Abstract: Millimeter astronomy with the Atacama Large Millimeter Array (ALMA) will take a prominent role in astrophysical research this decade. A key topic will be the search for molecular gas -- the raw ingredient for star formation -- in the early Universe. I will give an extensive introduction on some of the successes and limitations thus far in the search for molecular gas in the distant Universe, focussed on the commonly used tracer carbon-monoxide or CO. I will address how the Australia Telescope Compact Array (ATCA) has overcome some of these limitations and is now a world-class open-access southern millimeter-facility and excellent compliment to ALMA in the search for distant molecules. We used the ATCA for a survey for molecular CO(1-0) gas in a sample of 14 high-redshift proto-cluster radio galaxies. These high-z radio galaxies are among the most massive and active galaxies in the early Universe and believed to be the progenitors of current day giant ellipticals in the cores of rich clusters. I will highlight results of two fascinating sample sources (the Spiderweb Galaxy and MRC 0152-209), which show evidence for widely spread reservoirs of cold gas that have not (yet) been depleted by star formation or radio source feedback. Results of our survey provide insights into the co-evolution of active black-holes and their massive host galaxies in the early Universe.
Slides: PDF

Date: 06 July (Fri) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Ultracool KIS
Speaker (Affiliation): Dr. Eduardo Martín Guerrero de Escalante - INTA-CSIC Centro de Astrobiología, Spain
Abstract: The Kepler INT survey (KIS) is an ongoing imaging survey of NASA's Kepler mission field of view. A search for ultracool dwarfs, very low-mass stars and brown dwarfs, in the KIS using the Spanish Virtual Observatory will be presented. The scientific prospects of Kepler observations of ultracool dwarfs using GO time will be presented.
Slides: PPT

Date: 04 July (Wed) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Ground-Based Follow-Up Observations of the Kepler Asteroseismic Targets
Speaker (Affiliation): Dr. Joanna Molenda-Zakowicz, Astronomical Institute - University of Wroclaw, Poland
Abstract: The NASA space mission Kepler has been providing high-precision time-series photometry in a single, broad-band filter for thousands of stars since March 2009. As in April 2012 NASA approved the extension of the Kepler mission, those observations will be continued for another four years. The Kepler data allowed to discover more than 60 exoplanets, and to study new or already known but poorly investigated astrophysical phenomena in stars of different kinds. However, the full use of the Kepler observations is possible only if they are completed with ground-based spectroscopic and photometric data. Keeping that in mind, an enormous observational effort has been undertaken by the astronomical community which aims at deriving the atmospheric parameters of the Kepler targets, computing the cluster membership of the stars falling into the open clusters in the Kepler field of view, and classifying the variable stars to the types of variability. In this talk, I give an account of the present state of the photometric and spectroscopic monitoring of the Kepler field, the results which have been already obtained, and the progress of the on-going work.
Slides: PDF

Date: 20 June (Wed) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: The Planck Mission: Early Results
Speaker (Affiliation): Dr. Jose Alberto Rubiño-Martín, Instituto de Astrofísica de Canarias, Spain
Abstract: The European Space Agency's Planck satellite was launched on 14 May 2009, and has been surveying the sky stably and continuously since 13 August 2009. Its performance is well in line with expectations, and it will continue to gather scientific data until the end of its cryogenic lifetime. I will present the first scientific results of the mission, which appeared as a series of 26 papers at the beginning of 2011, covering a variety of astrophysical topics. In particular, I will focus on the results on galactic diffuse emissions, as well as the first results on galaxy clusters detected by means of the Sunyaev-Zeldovich effect.

Date: 31 May (Thu) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: Dwarf Galaxies
Speaker (Affiliation): Dr. Ovidiu Vaduvescu, Isaac Newton Group of Telescopes and IAC Associated
Abstract: I will present my research interests in dwarf galaxies, specifically dwarf irregulars (dIs), blue compact dwarfs (BCDs) and dwarf ellipticals (dEs). First, I will explain my preference to observe galaxies in the near infrared (NIR), sharing some experience in the difficult task of imaging, reducing and measuring extremely faint surface dwarfs observed with many facilities (2MASS, IRSF, OAN-SPM, INT, NTT, TNG, CFHT, Blanco, Gemini and VLT). Second, I will list some main science results, such as the new "sech law" to fit surface profiles of dIs and BCDs and the "dwarf fundamental plane" (FP) that recently lead to some insights in some fundamental physics linking star forming dwarfs. Third, I will present some spectroscopical and chemical results about star forming dwarfs located in the Local Volume (LV) and nearby clusters (Virgo, Fornax, Hydra, Antlia, Perseus). Finally I will present some recent and future projects including dwarfs and giants in different environments, where I gladly welcome students or new collaborators.
Slides: PPT

Date: 09 May (Wed) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Young, massive, and poweful ...
Speaker (Affiliation): Dr. Cecilia Farina, Isaac Newton Group of Telescopes
Abstract: Massive stars (M > 10 Ms) constitute a small fraction of the whole stellar population of a galaxy and the time scales involved in their evolution are short (in the order of a few million years). Nevertheless, these objects play a fundamental role in the dynamical and chemical evolution of galaxies. During all their evolutionary stages, massive stars interact violently with the interstellar medium: injecting kinetic energy through their strong stellar winds, providing most of the ionizing photons in the galaxies as well as the heavy chemical elements that will be recycled in the new stellar generations. Whereas in the last few decades, knowledge of the physical processes involved in massive star formation has greatly increased, both from theoretical and observational points of view, there are still basic issues in the field which are not clearly understood. These uncertainties originate from the complexity of the environments where massive star formation proceeds, which makes observational studies of massive star formation regions a challenging task. In this talk I will give a brief summary of massive stars and massive formation regions at different scales, from an observational perspective. I will also review the fundamentals of studying these regions at infrared wavelengths. This will provide the context to present a near infrared study of the youngest and more massive stellar population of NGC 604, the second major giant HII region in the Local Group after 30 Doradus.
Slides: PDF

Date: 04 Apr (Wed) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Kepler's treasure chest of eclipsing binary stars
Speaker (Affiliation): Dr. Steven Bloemen, Institute of Astronomy, Leuven University, Belgium
Abstract: While the Kepler satellite was designed to hunt for planets, its precise photometric observations of about 150 000 stars have also proven to be of immense value to the binary star community. More than 2000 previously unknown eclipsing binary stars have been found, which can all be studied in detail thanks to the nearly continuous Kepler datasets that will span at least 3.5 yrs. During this talk we will dig into Kepler's treasure chest of eclipsing binaries. We will discuss scientific highlights such as the first discoveries of circumbinary planets, binaries with components that show tidally excited oscillations, and compact binaries in which the detections of Doppler beaming and Rømer delay allowed us to measure the components' radial velocity amplitudes directly from the photometric data.

Date: 19 March (Mon) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Status of the NAOMI upgrade
Speaker (Affiliation): Dr. Jure Skvarc, Issac Newton Group of Telescopes
Abstract: NAOMI, the adaptive optics system at the WHT, is undergoing several upgrades in last three years in order to improve reliability and stability. I will present an overview of the work done on environmental control, optical components, detectors, software at the user level and the real time system, as well as the hardware upgrades of real time system. First results of the on-sky tests of the new real time system will be presented, both for infrared imaging with INGRID and optical imaging with the Andor EMCCD camera. In addition, some results obtained with lucky imaging technique will be shown. Although some more on-sky tuning is necessary to get the optimal performance, the initial results show that the upgrade is progressing well and that the work to replace the entire NAOMI real time system can continue with the goal to further improve reliability and performance, as well as to simplify the system.

Date: 14 March (Wed) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: The formation of S0 galaxies
Speaker (Affiliation): Prof. Dr. Alfonso Aragon-Salamanca, School of Physics & Astronomy, University of Nottingham, UK
Abstract: Evidence is mounting indicating that S0s were once spiral galaxies that ceased forming stars and subsequently changed their morphology. Studying the timing, location and physical mechanism(s) involved in this transformation is not only interesting in itself, but it can also provide very useful clues on how galaxies evolve and the possible role of the environment. During the last few years we have been following several lines of research to test whether this transformation is indeed taking place, find out where it happens, and look for the physics driving it. At low redshift we have studied in detail the final products of the transformation - the S0s themselves - while at intermediate redshifts (z~0.5) we have concentrated on the putative progenitors - spiral galaxies - and the galaxies caught in the act of transforming. In this talk I present some of our more interesting results. Although there are still some loose ends, a coherent picture may be emerging.
Slides: PDF

Date: 14 March (Wed) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: INO340 project; status and future plans
Speaker (Affiliation): Dr. Habib Gharar Khosroshahi, Institute for Research in Fundamental Science, Iran
Abstract: Iranian National Observatory (INO) project aims at construction of a 3.4m optical telescope currently being designed. The observatory site is located at an altitude of 3600m in the central Iran mountains benefiting from very good observing conditions. This general purpose optical telescope demanded to offer high resolution imaging over a relatively large field of view. Imaging and spectroscopic follow-up observations of ground and space based surveys are among the key science objectives of this telescope. Given its longitude, it can also be efficiently used for the time domain observations. Just a few days after the CoDR, I will report on the progress in different areas, optical design, mechanics, infrastructure and many more. The INO340 is more than a telescope!
Slides: PDF

Seminars in 2011

Date: 14 Dec (Wed) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: New Insights into the Galaxy Morphology-Density Relation
Speaker (Affiliation): Dr. Peter Erwin, Max-Planck-Insitute for Extraterrestrial Physics, Garching
Abstract: Galaxy morphology is known to be directly related to galaxy environment, but how this varies outside of dense clusters is poorly understood, and whether hierarchical formation models can correctly predict this is also unclear. I present the recent work on relating the detailed morphology of local galaxies to group environment on a variety of scales, from single-galaxy halos to the most massive groups, and compare these empirical findings with modern semi-analytic models which account for the full merger history of galaxies. We find contrasting trends for elliptical and S0 galaxies, which suggests two different formation channels for the latter.

Date: 28 Nov (Mon) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Double white dwarfs and the connections between hot subdwarfs, R,CrB stars and extreme helium stars
Speaker (Affiliation): Prof Simon Jeffery, Armagh Observatory and Trinity College Dublin
Abstract: The proposal that the merger of two white dwarfs would form a major channel for the formation of hot subdwarfs has been current for over two decades. Naturally, such a merger would result in a single star, rather than a binary. The consequences for frequency, mass distribution, rotation velocity, surface composition, and so on are less obvious. This talk will review the general picture of double white dwarf mergers, including links between white dwarf mergers and various classes of evolved star. It will present recent work on: a) links between main-sequence binaries and double white dwarf merger progenitors, b) stellar evolution calculations following the merger of two white dwarfs, and c) the correlation between predicted and observed surface abundances of post white-dwarf mergers.

Date: 28 Sep (Wed) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: The Telescopes, Instrumentation and Operations of the AAO
Speaker (Affiliation): Dr. Chris McCowage, Former staff member of AAO Australia and ING La Palma
Abstract: The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, operates the 3.9 metre Anglo-Australian Telescope (AAT) and the 1.2 metre United Kingdom Schmidt Telescope (UKST) at Siding Spring Observatory which is operated by the Research School of Astronomy & Astrophysics, Australian National University. The telescopes and instrumentation will be described together with the operations model. There will be a particular emphasis on the development of the use of optical fibres in AAO astronomical instrumentation including 2dF, 6dF and AAOmega. Other topics to be touched on include future instrumentation and technology developments including the use of photonics, changes to AAO governance with the withdrawal of the United Kingdom and external instrumentation projects for other observatories.
Slides: PDF

Date: 10 June (Fri) Time: 12:00am Place: 6th floor meeting room, Mayantigo building
Title: The Myth of Haumea
Speaker (Affiliation): Mike Brown, CALTECH, USA
Abstract: Haumea is perhaps the strangest object in the Kuiper belt. It has a faster rotation, greater elongation, and higher density than almost anything in the Kuiper belt. It is surrounded by a pair of moons and has a family of much smaller objects in nearly identical solar orbit which appear to have the composition. I will discuss the causes of these strange properties and show the latest observations on trying to unravel the history, physics, and chemistry of this odd dwarf planet.
Slides: PPT

Date: 17 February (Thu) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Time-Resolved Properties of the White Light Continuum During Stellar Flares
Speaker (Affiliation): Adam Kowalski, Astronomy Department, University of Washington
Abstract: The primary mode of radiative energy release in stellar flares is in the optical and near-ultraviolet (NUV) continuum. This white light radiation carries a large fraction of the total radiated flare energy. However, radiative hydrodynamic models of stellar flares using a solar flare paradigm and the sparse observations of solar and stellar flare continua are all seemingly in disagreement over the type(s) of emission that contribute to the optical/NUV continuum during flares. We have begun a long-term spectroscopic flare monitoring campaign to fully characterize the optical/NUV white light continuum emission on short timescales for large and small flares. To date, our most significant results come from spectroscopic (3350A - 9260A) and photometric (U band) observations during 1.3 hours of the decay phase of a megaflare on the dM4.5e star YZ CMi, where we have detected multiple continuum components that contribute to the white light. I will present the continuum and emission line properties of this flare and initial phenomenological modeling of the flaring atmosphere. I will also compare the continuum properties to ultra-high speed observations of smaller flares.
Slides: PDF

Date: 9 February (Wed) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Gravitational wave sources and the (future) use of the La Palma telescopes
Speaker (Affiliation): Prof. Paul Groot, University of Nijmegen, The Netherlands
Abstract: The gravitational wave domain remains the last completely unopened window on the Universe. Ground-based high frequency detectors are already operational, but lack known sources. The low-frequency domain will be opened by the LISA space interferometer. The only known LISA sources are ultracompact white dwarf binaries. In a campaign involving many of the La Palma telescopes we are uncovering and characterizing the Galactic population of these ultracompact binaries, with orbital periods as short as 5.6 minutes. In the talk I will give an overview of the current state of affairs, our use of the La Palma telescopes, and the (possible) future (combined) use of the telescopes.
Slides: PDF

Date: 21 January (Fri) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Accelerating Universe, Dark Energy or Modified Gravity
Speaker (Affiliation): Shant Baghramian (Department of Physics, Sharif University of Technology Tehran, Iran)
Abstract: First, I will give a very brief description of the accelerating universe state and its cosmological evidence like SNIa, CMB and the LSS. Then I propose the Cosmological constants (LCDM-model) and its alternative Dark energy (DE) and Modified gravity (MG) models as plausible candidates for describing the accelerating Universe. Some cosmological observations, especially large scale structure probes such as matter power spectrum, the ISW effect and growth index are discussed later, as useful tools to distinguish between viable DE and MG models which are equivalent in predicting the background dynamics of Universe. Finally, the reconstruction of the dynamics method as a probable way for investigating the problem is introduced, and the future prospects on the issue is discussed.
Slides: PDF

Seminars in 2010

Date: 10 December (Fri) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Filter Measurements for ACAM
Speaker (Affiliation): Annemieke Janssen (Rijks Universiteit Groningen & ING student)
Abstract: During the last three months the Transmitted Wavefront Distortions (TWD) of almost all 50-mm filters have been measured. These distortions are important to know since they affect the image quality of ACAM observations. For other instruments the TWD is less critical since filters are usually placed in the focal plane, where they only affect the image quality locally. ACAM is a bit of an exception having the filters placed near the pupil plane, where wavefront distortions over the whole filter area affect the image quality.

We started analysing the results, partly with Zemax and partly with pinhole experiments. In the last case, calibration lamps and a pinhole in ACAM create a very tiny spot on the CCD. The effect of a filter placed in the beam can now be compared with the measured TWD. The first results will be discussed in an half-hour presentation.

Slides: PDF

Date: 9 December (Thu) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Dark matter in galaxies
Speaker (Affiliation): Marc Balcells (ING)
Abstract: This seminar is part of an initiative coordinated from SISSA to present the phenomenology of dark matter in galaxies at seminars in as many institutes as possible, in a single 'Dark Matter Awareness Week' ( ). Over 150 institutes have listed up to hold such seminar. La Palma is of course represented. The ING makes a special invitation to astronomers from all ORM institutions to attend this event at Mayantigo, where the evidence for DM in galaxies will be reviewed. Below is the official abstract proposed by the DMAW organisers.

We discuss the details of the mass discrepancy phenomenon in galaxies usually accounted by postulating the presence of a non luminous component. In the theoretical framework of Newtonian gravity and Dark matter halos we start by recalling the properties of the latter as emerging from the state-of-the-art of numerical simulations performed in the current LCDM scenario of cosmological structure formation. We then report the complex and much-telling phenomenology of the distribution of dark matter in spirals, ellipticals, and dwarf spheroidals. Care will be given to show that such a coherent observational framework is obtained from different and large samples of galaxies and by means of very different methods of investigation and by exploiting different tracers of the gravitational field. These include rotation curve and dispersion velocities mass fitting, X-ray gas property analysis, weak and strong lens signal mass decomposition, analysis of halo and baryonic mass functions! We will then highlight the evidence that the distribution of dark and luminous matter are closely correlated. Hints on how the empirical scenario of the mass distribution in galaxies, including the Milky Way and the nearby ones affects the cosmological investigations are given throughout the talk. Among them, the theoretical constraints on the elusive nature of the dark matter particles and its direct and indirect searches.


Date: 16 November (Tue) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Using AF2/WYFFOS (and Spitzer) to investigate terrestrial planet formation around young stars
Speaker (Affiliation): Rob Jeffries (Astrophysics Group, Keele University)
Abstract: Our own terrestrial planetary system is thought to have formed during the first 5-50 Myr of the solar system, but direct evidence for terrestrial planets around other stars is hard to obtain. I will describe a joint program of WHT spectroscopy and Spitzer photometry that seeks indirect evidence for the formation of terrestrial planets in the form of 24 micron excesses from young (~25 Myr) solar-type (F-K) stars in the IC 4665 open cluster. Membership of the cluster and stellar parameters have been obtained using optical photometry and a WYFFOS spectroscopic survey. I report on oddly effective lithium depletion in the cluster, casting doubt on the use of this diagnostic as a reliable age indicator in very young stars. The membership list is combined with a Spitzer survey to identify stars with mid-IR excesses. We determine that 42(+18-13)% of the solar-type (F5-K5) cluster members have excess emission at 24 microns indicative of debris discs, the highest frequency of the clusters studied with Spitzer to date. The majority of these discs have intermediate levels of excess and no source is found to have extreme levels of excess indicative of a recent transient event (like the collision that formed the Earth-Moon system) as opposed to steady-state collisional evolution.

Date: 22 October (Fri) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Dynamical Studies of the Globular Cluster Systems around the Giant Elliptical Galaxies NGC4636 and NGC1399
Speaker (Affiliation): Ylva Schuberth (Argelander-Institut fur Astronomie, Bonn, Germany)
Abstract: Dark matter (DM) studies in elliptical galaxies were long hampered by the lack of suitable dynamical tracers. The advent of 8m-class telescopes equipped with multi-object spectrographs has made it possible to use globular clusters (GCs) as dynamical probes constraining their host galaxy's gravitational potential. I will present results for the two largest samples of globular cluster velocities obtained for giant elliptical galaxies to date: The galaxies studied are NGC4636 located in the very outskirts of the Virgo cluster of galaxies and NGC1399, the central galaxy of the Fornax cluster. Owing to its unusually bright X-ray halo, NGC 4636 has a reputation of being extremely dark matter dominated. The Jeans Models for its GC system, however, require significantly less DM than suggested by the X-ray studies. The extremely populous GC system of NGC1399 has an extent of at least 250 kpc, which is comparable to the core radius of the Fornax cluster itself. Here, the mass estimates obtained from the combined analysis of the GCs and the stellar velocity dispersion profile agree with the values from X-ray studies in the inner 100 kpc. At larger radii, however, we do not find any evidence for a transition from a galaxy to a cluster halo, as suggested by X-ray work.

Date: 16 September (Thu) Time: 03:30pm Place: 6th floor meeting room, Mayantigo building
Title: Early time GRB follow-up with BOOTES
Speaker (Affiliation): Martin Jelinek (IAA-CSIC Granada)
Abstract: BOOTES is a robotic telescope/observatory network primarily designed for follow-up of Gamma-Ray Bursts (GRB). Telescopes are relatively small but fast and their "specialization" is the first hour after the GRB explosion. The operation of the telescopes is automated up to the high degree so that the observatory can work unattended for weeks. I will discuss observational properties of GRBs. What and how we observe, what is needed and what is not.

Date: 2 July (Fri) Time: 11:00am Place: R. Pallavicini Tesi meeting room, FGG-INAF (Rambla J.A. Fernandez Perez 7, San Antonio)
Title: CoRoT and its rich exoplanet harvest
Speaker (Affiliation): Davide Gandolfi (Research and Scientific Support Department, ESA/ESTEC)
Abstract: Studies of transiting extrasolar planets are cornerstones for understanding the nature of planets beyond the Solar System since a wealth of precious information can be gained. The space telescope CoRoT is the first space mission devoted to the discovery of extrasolar planets via the transit method using photometric measurements of high accuracy. The transiting extra solar planets recently detected by CoRoT show the capability of the instrument to enlarge the parameter space of extra-solar planets and explore the transition regimes between gaseous giant and terrestrial planets, and gaseous giant planets and brown dwarfs. In this talk I will review the recent results from CoRoT observations and complementary ground-based photometric and spectroscopic follow-ups. The physical parameters of the new transiting planets and their host star discovered so far by CoRoT, will be presented and discussed.

Date: 22 June (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: A Lucky Imager System for the WHT
Speaker (Affiliation): Craig Mackay (Cambridge Institute of Astronomy, UK)
Abstract: A new method of imaging in the visible has given the highest resolution images ever taken anywhere. It needs a natural guide star of only 18.5 mag (I band) and delivers a corrected field over almost 1 arcmin. This talk will show how it can be done on the WHT, the VLT and even on the GTC.

Date: 24 May (Mon) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Space weathering mechanisms insight Near-Earth Objects
Speaker (Affiliation): Mirel Birlan (Institut de Mecanique Celeste et de Calculs des Ephemerides (IMCCE), Observatoire de Paris)
Abstract: Space weathering is influencing in a very important manner the atmosphereless bodies. The consequence of this effect to the surfaces in the visible and near-infrared domains is the reddish slope of the spectrum corroborated with a decreasing of the albedo, and (if exists) the decrease of absorption bands. However, the spectral response of the surfaces of a class of Near-Earth Objects (Q-type taxonomic class) shows physical properties of surface minerals less affected by space weathering. This result is intriguing while these objects are closer to the Sun, thus exposed to an important interaction with the solar wind. The close encounters of these bodies with telluric planets seem to be the most probable mechanism of such phenomenon. I will present some recent results concerning NEOs and I will place these researches in the global context of small solar system bodies.
Slides: PDF

Date: 13 May (Thu) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: Chemical abundances in the polar disk of NGC4650A: implications for cold accretion scenario
Speaker (Affiliation): Marilena Spavone (Università di Napoli Federico II)
Abstract: The aim of the present study is to test whether the cold accretion of gas through a "cosmic filament" (Maccio' et al. 2006) is a possible formation scenario for the polar disk galaxy NGC 4650A. If polar disks form from cold accretion of gas, the abundances of the HII regions may be similar to those of very late-type spiral galaxies. The deep spectra available allowed us to measure the Oxygen abundances (12 + log (O/H)) using the "Empirical method" based on intensities of the strongest emission lines, and the "Direct method", based on the determination of the electron temperature from the detection of weak auroral lines. The low metallicity value in the polar disk NGC 4650A and the flat metallicity gradient are both consistent with a later infall of metal-poor gas, as expected in the cold accretion processes.

Date: 6 April (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Photometric and structural properties of dwarf galaxies in the Coma cluster
Speaker (Affiliation): Mark den Brok (Kapteyn Astronomical Institute, University of Groningen)
Abstract: The formation of dwarf galaxies in clusters is still an unsolved problem. Models of galaxy formation underpredict the number of observed dwarfs. Additionally, it is not clear which of the mechanisms that have been proposed to remove gas from dwarf galaxies dominates. In this talk, we present results from the Coma Cluster ACS Treasury Survey on photometric properties of dwarf galaxies, for which we have studied colours, colour gradients and structural parameters. Owing to the high sensitivity and resolution of our data, we are able to separate out the nuclear and the remaining components of dwarf galaxies and study the stellar populations of each component separately. Our results on colour gradients show that metallicity gradients in dwarf galaxies form a continuous sequence with elliptical galaxies, becoming shallower for fainter galaxies. I will discuss the relation between colour gradients and other photometric and structural properties, such as the presence of and stellar populations of nuclear star clusters.

Date: 10 March (Wed) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Heavy element abundances in the second parameter globular cluster pair NGC288 / 362
Speaker (Affiliation): Paul Anthony Wilson (NOT Student, University of Oslo)
Abstract: I will present the results from my master thesis where I measured and assessed the relative abundance ratios of heavy elements (Si to Eu) in the second parameter pair NGC 288 and NGC 362. This is needed in the context of the 2nd parameter problem which, as of yet, does not have a satisfactory solution. Studies such as this one are important for providing constraints upon the uniformity of mixing in the protocluster environment and for constraining the role of heavy element abundance as a 2nd parameter candidate.

Date: 26 February (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Variability and stability in optical blazar jets: photopolarimetric monitoring of OJ287 in 2005-2009
Speaker (Affiliation): Carolin Villforth (Space Telescope Science Institute, USA)
Abstract: Blazars are a subclass of AGN with jets pointing almost directly towards the observer, making them perfect object for studying the properties of AGN jets. We present photopolarimetric monitoring of the blazar OJ287 and discuss implications for jet physics. Additionally, this particular object is of special interest as it has shown regularly appearing double-peaked bursts and is therefore suspected to host a supermassive binary black hole. Our data can also be used to assess different binary black hole models.

Date: 12 February (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: SHARDS: Understanding the mass assembly of galaxies at 0
Speaker (Affiliation): Pablo G. Pérez-González (Universidad Complutense de Madrid)
Abstract: We will present the main results of our research about the assembly of galaxies at z<4 based on observations obtained by the deepest surveys, noticeably including mid- and far-IR data taken with Spitzer. Analyzing SFR and stellar mass functions in several redshift bins at 0

Date: 9 February (Tue) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: The faint extragalactic radio source population
Speaker (Affiliation): Chris Simpson (Liverpool John Moores University)
Abstract: With LOFAR and e-MERLIN about to start taking data, and SKA on the horizon, I will describe what we know about the composition of the extragalactic radio source population and, in particular, the advances that have been made in understanding the microJansky sources. I will then look to the future to discuss what progress is likely to be made in addressing the existing uncertainties in our current picture.

Date: 5 February (Fri) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: The making of planetary embryos
Speaker (Affiliation): Cornelis Dullemond (Max Planck Institute for Astronomy, Heidelberg)
Abstract: Making planets out of dust is one of Nature's tricks that we still haven't understood well. This is remarkable, because modern science has struggled with this question for many decades. Recent developments in observations of protoplanetary disks and exoplanetary systems, new developments in numerical models of the planet formation process, as well as over a decade of laboratory experiments of colliding dusty bodies, have shed new light on this issue. But this new information is cryptical: it is not obvious how to derive an answer to the above question from it. I will talk about various theoretical modeling efforts that try to synthesize these various crytic pieces of the puzzle to obtain a full picture, though I will focus my talk on the growth process from dust to "planetary embryos", i.e. thousand-kilometer size planetary building blocks. I will show that while some answers are found, new questions are raised. Most importantly, I will show how current and future observations of various kinds (can) put constraints on these models.

Date: 15 January (Fri) Time: 11:00 Place: 6th floor meeting room, Mayantigo building
Title: Developing global observatory network - the software environment of the Bootes observatories and other
Speaker (Affiliation): Petr Kubanek (Image Processing Laboratory, Universitat de Valencia, and IAA, Spain)
Abstract: I will present an open source system we are developing for control of various, usually fully autonomous, observatories. The system is capable taking care of the weather, selecting targets for observations, and doing basic image image processing. The system is called RTS2 and is being developed for almost a decade, and controlling more then 10 observatories. It primary task was a quick follow ups observations of Gamma Ray Bursts fields, but it is now making progress towards a generic observatory control environment. It design philosophy, lessons learned during development, as well as some of the results obtained will be presented.
Slides: PDF

Title: Abell 41: Nebular Shaping by a Binary Central Star?
Speaker (Affiliation): David Jones (Jodrell Bank Centre for Astrophysics, Univ. of Manchester, UK)
Abstract: Although the theoretical link between bipolar planetary nebulae and binary central stars is long established, there is little observational support for this hypothesis. Here, I will discuss some of the observational tests being employed to evaluate the validity of the hypothesis, before focussing on one particular 'test-case' object.

Abell 41, one of a small percentage of planetary nebulae known to contain a central binary system, in this case the well-studied, close-binary MT Serpentis. As such, Abell 41 represents an ideal object to test the so-called 'Binary Hypothesis'. I present detailed spatio-kinematic modelling, based on deep narrow-band WHT-ACAM imagery along with high resolution MES-SPM longslit spectroscopy, in order to determine the relationship between the plane of the central binary and any nebular symmetry axis. Thus, testing one of the fundamental predictions of all theories of binary-induced nebular shaping, that the nebular symmetry axis will be perpendicular to the plane of the central binary.


Seminars in 2009

Date: 17 December (Thu) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: Integral Field Spectroscopy of Star-Forming Regions in M33
Speaker (Affiliation): Jose M. Vílchez (IAA-CSIC, Granada, Spain)
Abstract: We present an ongoing project of Integral Field Spectroscopy (IFS) of the giant star-forming regions of M33. These observations are intended to study the variations in 2D of the main physical and chemical properties across the HII region complexes, selected to sample the metallicity gradient of M33. IFS is a powerful technique: at each position of the observed field, the full optical spectrum from 3650 to 6990 A was obtained. We have created maps of the most relevant emission lines and line ratios for all the giant HII regions of the sample. Among these regions, a detailed study of NGC595, the 2nd brightest HII region in M33, is presented. The extinction map and the fraction of the absorbed Halpha luminosity were derived and compared to the Mid Infrared emission measured by Spitzer. In addition, the total census of Wolf-Rayet stars, the ionisation structure and star clusters of the region as well as its shell morphology and the density distribution have been analysed. Finally, our IFS has provided a simple way to examine the reliability of some popular metallicity calibrators currently used to characterize the most distant emission line galaxies.
Slides: PDF

Date: 14 December (Mon) Time: 17:00 Place: 6th floor meeting room, Mayantigo building
Title: RaTS and the search for Ultra-Compact binaries
Speaker (Affiliation): Gavin Ramsay (Armagh Observatory, UK)
Abstract: Ultra Compact Binaries are predicted to be the strongest known sources of gravitational waves in the LISA pass-band. Since they are at the short period end of the orbital period distribution (<70 mins), their number is a sensitive test of binary evolutionary models. The best method to detect these short period systems, whose optical light is dominated by an accretion disk and show optical intensity variations on timescales close to their orbital period, is through deep, wide-field, fast-cadence photometric surveys. The RaTS (Rapid Temporal Survey) project is unique in that it is sensitive to variability on timescales as short as 2 mins and systems with V~22. Our strategy and initial results will be presented.
Slides: PDF

Date: 30 November (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Observational studies of gas in protoplanetary disks
Speaker (Affiliation): Andres Carmona Gonzalez (Astronomical Observatory, University of Geneva)
Abstract: Circumstellar disks are essential in the process of star and planet formation. Early in the star's life they permit the inflow of material from the primordial cloud to the star and the outward transport of angular momentum. During the pre-main sequence, also known as the T Tauri phase, these reservoirs of dust and gas are the sites of planet formation. Although protoplanetary disks are composed of 99% gas and only 1% dust, our physical understanding of these disks has been based mostly on the study of dust emission. The dust dominates the opacity, therefore, it is much easier to observe. However, as the gas is the dominant mass component, to derive observational constraints of gas properties in the disk is fundamental for our understanding of disk physics, therefore, planet formation. Several fundamental questions about planet formation remain unanswered: How much material is available for forming planets? How long is the disk life-time? How does the disk dissipate? What are the dynamics of disks? The answers to these questions will require direct observational constraints of the gas, especially from the region where planets are expected to form (R<10AU). The advent of high-resolution spectrographs in the IR opened the way to the observational study of the gas in the inner disk. In this talk I will review I discuss several observational diagnostics in the UV, optical, near-IR, mid-IR, and (sub)-mm wavelengths that have been employed to study the gas in the disks of young stellar objects. I will concentrate in diagnostics that probe the inner 20 AU of the disk, the region where planets are expected to form. I will discuss the potential and limitations of each gas tracer, what we have learned and present prospects for future research. In addition, I will discuss briefly our current project with NOTCAM: NIR spectroscopy of candidates to young stellar objects in Taurus. Reference: Carmona, A. 2009

Date: 24 November (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Optical and NIR studies of short period low mass X-ray binaries (LMXB)
Speaker (Affiliation): Pasi Hakala (Tuorla Observatory, University of Turku, Finland)
Abstract: I present some recent results from our Optical and NIR studies of five short period LMXB's (X1822-371, X1957+115, UW CrB, X1916-05 and X0614+091). Optical photometry and spectroscopy reveal some surprising results on the geometry and evolution of accretions discs in LMXB's. Based on our data, it is increasing clear that accretion discs in these systems are far from being stable and must undergo substantial precession and/or warping behaviour on timescales less than a day in case of the shortest period systems.

Date: 20 November (Tue) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Star-forming Galaxies in the Hercules Cluster: Spectroscopic Properties
Speaker (Affiliation): Vasiliki Petropoulou (IAA)
Abstract: I will present preliminary results of the spectroscopic follow-up of a sample of star forming galaxies in the Hercules cluster, performed with INT/IDS and WHT/ISIS. The sample was defined by the Halpha imaging survey in the central region of the A2151 cluster, performed by our group (Cedres et al. 2009). The central goal of this project is to study the impact of the cluster environment on the evolution of these galaxies and search for observable imprints on their photo-chemical evolution.
Slides: PDF

Date: 23 October (Wed) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: A new review of accurate stellar masses and radii
Speaker (Affiliation): Johannes Andersen (NOT)
Abstract: A new review of accurate stellar masses and radii has been performed. We find 95 detached binary systems in which the components have basically evolved as single stars and have mass and radius determinations to 3% accuracy or better. 21 systems have spectroscopic metallicities as well. Effective temperatures, reddening, rotational velocities and approximate ages are also provided when possible. We discuss the use of the data to test models of stellar structure and evolution, the properties of mildly active stars, and the tidal evolution of the stars and their orbits, including the implications for general relativity.
Slides: PPT | PDF

Date: 21 October (Wed) Time: 11:00am Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: Analysis of asteroid Steins resolved surface from Rosetta spacecraft
Speaker (Affiliation): Sara Magrin (Dipartimento di Astronomia, Padua University)
Abstract: On September 5th 2008 the Rosetta spacecraft had a fly-by with the main belt asteroid Steins, at a distance of about 800 Km from the body. OSIRIS WAC and NAC (Wide Angle and Narrow Angle Cameras) observed the 5 Km sized object at different phase angles with different filters. To analyze the possible color variegation of the surface of Steins we developed an IDL tool to produce pixel per pixel (rough) spectra, by using values of albedo in three different filters at a time. The results of this analysis performed on the data obtained by the NAC camera will be shown.

Date: 13 October (Tue) Time: 16:30 Place: 6th floor meeting room, Mayantigo building
Title: Overview of the European Extremely Large Telescope
Speaker (Affiliation): Isobel Hook (Dept. of Astrophysics, Univ. of Oxford)
Abstract: The European ELT is now in the detailed design phase, leading to a proposal for construction that will be presented to ESO Council in late 2010. If approved, the ELT will see first light in around 2018. In this talk I will present a summary of the science case, which ranges from studies of exo-planets to the most distant galaxies and cosmology. I will show some recent results from science simulations developed as part of the Design Reference Mission. I will also give an overview of the telescope and the ELT instrument studies that are currently underway.
Presentation: On DVD, please contact Javier Méndez.

Date: 9 October (Fri) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: The 6.5 m MMT's f/5 instruments - with a focus on high-resolution multi- and single-object spectroscopy
Speaker (Affiliation): Gabor Furesz (Smithsonian Astrophysical Observatory Cambridge, MA, USA)
Abstract: In this talk I briefly review the f/5 wide field optics and instruments built by SAO for the 6.5m MMT telescope: the 1.7m diameter f/5 secondary, the f/5 corrector lens and ADC prism, wavefront sensor, the 1/2 deg imager Megacam, the multi-slit NIR imaging spectrograph MMIRS, the NIR camera SWIRC, the low and high res multi-object spectrographs Hectospec and Hectochelle, and Binospec, the dual-beam high throughput VIS multi-slit imaging spectrograph. I'll discuss some of the technical details in optical mounting and design, which were the results of SAO's internal R&D work, and potentially can be very benefitial for future instrument developments by other groups. During the second part of the talk the focus will be on high resolution spectroscopy. I'll discuss the Hectochelle instrument in more detail, the pros and cons of this multi-object echelle in comparison of other similar instruments, and in the light of measuring precision radial velocities (PRV). After showing some of the scientific results of Hectochelle on cluster dinamics we will shift to PRV measurements on single stars, as the key tool for exoplanet research. In this 3d part I'll summarize SAO's instrumental and scientific experience on some of the important instrumental and scientific aspects of PRV work, based on our involvment in the HAT-Net, Kepler, HARPS-Nef and GMT projects.
Presentation: On DVD, please contact Javier Méndez.

Date: 23 September (Wed) Time: 11:00am Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: Deep LBT photometry of VV124: an isolated dwarf galaxy falling into the Local Group
Speaker (Affiliation): Michele Bellazzini (INAF - Osservatorio Astronomico di Bologna)
Abstract: VV124 == UGC4879 has been recently recognized as a dwarf galaxy lying in the outskirts of the Local Group (Kopylov et al. 2008). I present the preliminary results from our very deep LBT observations of this galaxy. We derived a Color-Magnitude diagram reaching r=26.5, down to ~4 mag below the RGB Tip and more than two magnitude deeper than previously available photometries. We obtain a very clean detection of the RGB tip, deriving a distance of 1.3 Mpc. Our CMD reveals that the galaxy is dominated by an old and metal-poor population, and it displays a metallicity gradient; a tentative detection of and extended HB and RR Ly population is also obtained. Coupling surface photometry and star-counts we are able to trace the Surface Brightness profile of the galaxy out to ~5' (=2 kpc), that is 5 times more extended than previous studies. We provide some interesting evidences suggesting that VV124 is a good representative of the pristine status of dwarf Spheroidal galaxies, before that close interactions with the main galaxy they are orbiting around transformed them into the very Low SB system we observe today.

Date: 21 August (Fri) Time: 12:00am Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: CTA: toward the next generation of Cherenkov Telescopes
Speaker (Affiliation): Angelo Antonelli (INAF - Osservatorio Astronomico di Roma)
Abstract: Very-high-energy gamma-ray astronomy has witnessed a major breakthrough with the physics results obtained by ground-based instruments during the last few years. These results have demonstrated impressively the huge potential of this field, not only in the area of astrophysics, but also in particle physics and cosmology. However, it also became apparent that the performance of current instruments is not sufficient to tap the full physics potential. The answer of the European VHE energy community to that challenge is the Cherenkov Telescope Array (CTA). In this talk I will shortly review the CTA project.

Date: 8 July (Wed) Time: 12:00 Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: An overview to the interacting binary class of Symbiotic Stars and the ongoing 2008-09 outburst of the system CI Cyg
Speaker (Affiliation): Bryce Croll, PhD Student (University of Toronto, Canada)
Abstract: We present an overview to the interacting binary systems knows as the name of Symbiotic Stars, in which a hot compact object (very often a White Dwarf) accretes material from a late type giant via stallar wing or Roche overflow. In particular we discuss about the early phases of the ongoing outburst that CI Cyg, a prototype of this class, is currently undergoing after thirty years of flat quiescence. The outburst started while the accreting WD was being eclipsed by the Roche-lobe filling M giant companion, and it was discovered during the egress phase on the second half of August 2008. The outburst reached peak V-band brightness in early October 2008 and has been characterized by amplitudes up to 1.9, in B band. At maximum V-band brightness, the outbursting WD had expanded to closely resemble an F3 II/Ib star, with M_V=-3.5, T_{eff} ~ 6900 K and R=28 R_{sun}. The high ionization emission lines ([NeV], [FeVII], HeII), so prominent in quiescence, disappeared, and only lower ionization lines (Balmer, HeI, SiII, FeII, [OI]) were visible. During the outburst, Balmer and HeI emission lines declined in equivalent width but increased in absolute flux. The output radiated by the hot component during the outburst corresponds to nuclear burning proceeding at a 2.10e{-8} M_{sun}/yr rate.

Date: 11 June (Thu) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Exploring the Diversity of Planets in other Solar Systems
Speaker (Affiliation): Bryce Croll, PhD Student (University of Toronto, Canada)
Abstract: I will discuss preliminary results from three ongoing observational projects that will form my thesis on extrasolar planets. I will present preliminary results from very recent CFHT WIRCam observations of the secondary eclipses of two of the hottest of the hot Jupiters in the near-infrared. We hope to detect the secondary eclipses of a number of hot Jupiters in the J, H and K near-infrared bands. I will touch upon progress from my ongoing project using GMOS on Gemini-South & North to search for atmospheric absorption from various chemicals in the transmission spectra of hot Jupiters. Lastly, I will discuss the preliminary results from our Spitzer IRAC 8.0 micron observations of the thermal phase curve of the eccentric (e~0.67) hot Jupiter HD 17156. Our observations are the first to probe more than one pseudo-spin period of an eccentric exoplanet. The goal of these observations is to detect the variation in thermal emission of the planet as a single face of the planet is flash-heated as it makes its "Big Swing" into periastron and then this flash heated face rotates in and out of view as the planet cools as it swings out towards apastron.
Slides: PDF

Date: 11 June (Thu) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Exploring the Diversity of Planets in other Solar Systems
Speaker (Affiliation): Bryce Croll, PhD Student (University of Toronto, Canada)
Abstract: I will discuss preliminary results from three ongoing observational projects that will form my thesis on extrasolar planets. I will present preliminary results from very recent CFHT WIRCam observations of the secondary eclipses of two of the hottest of the hot Jupiters in the near-infrared. We hope to detect the secondary eclipses of a number of hot Jupiters in the J, H and K near-infrared bands. I will touch upon progress from my ongoing project using GMOS on Gemini-South & North to search for atmospheric absorption from various chemicals in the transmission spectra of hot Jupiters. Lastly, I will discuss the preliminary results from our Spitzer IRAC 8.0 micron observations of the thermal phase curve of the eccentric (e~0.67) hot Jupiter HD 17156. Our observations are the first to probe more than one pseudo-spin period of an eccentric exoplanet. The goal of these observations is to detect the variation in thermal emission of the planet as a single face of the planet is flash-heated as it makes its "Big Swing" into periastron and then this flash heated face rotates in and out of view as the planet cools as it swings out towards apastron.

Date: 26 May (Tue) Time: 12:00 Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: Nine years of Solar System research using TNG
Speaker (Affiliation): Javier Licandro (IAC)
Abstract: In this talk I will present the major results of my research on surface properties of trans-neptunian objects and related minor bodies using TNG started in 2000. Results include the characterization of large TNOs like Eris, Makemake and, in particular, Haumea and the family of objects related with it; the determination of the surface characteristics of asteroids in cometary orbits; the mineralogy of Near Earth Asteroids and the relation with meteorites and main belt asteroids.

Date: 19 May (Tue) Time: 12:00 Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Speaker (Affiliation):
Abstract: Several astrophysical and cosmological tests demand a more accurate knowledge of the morphological distribution of clusters of galaxies. I will show how multi-wavelength observations allow to obtain information on the intrinsic three-dimensional shape of galaxy structures, and present results of our ongoing work on the subject and future applications.

Title: Post Common Envelope Binaries from the Sloan Digital Sky Survey
Speaker (Affiliation): Stelios Pyrzas, (ING & University of Warwick)
Abstract: While the majority of (wide) binaries evolve as if they were single stars, a fraction of them is expected to undergo a common envelope phase (CEp), giving birth to close binaries. The classes of objects affected by the CEp include supernova Ia progenitors, low mass X-ray binaries, ultracompact binaries and progenitors of short gamma ray bursts. Thus, Post Common Envelope Binaries (PCEBs), i.e. binaries that have undergone a CE phase during their evolution, play a key role in our understanding of close binary systems. Despite the clear importance, the current theoretical understanding of the CE phase is rather poor and underconstrained by observations. In this talk, I will present an ongoing project, aiming to build a large, well-defined sample of PCEBs, identified in the Sloan Digital Sky Survey (SDSS), with observationally determined stellar parameters. I will refer to the current status of the project, focus on the methods and techniques used and present important first results.

Date: 13 April (Mon) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: CSI: PN (CircumStellar Investigation: Planetary Nebula) - SuWt 2 and its mysterious central stars
Speaker (Affiliation): David Jones (ING & Jodrell Bank Centre for Astrophysics)
Abstract: It is generally believed that binary systems play a major role in the shaping of planetary nebulae (PNe), although to date there is little observational evidence linking PN morphologies to the parameters of their central star systems. In the case of SuWt 2, the star observed at its centre is a double A-type eclipsing binary with a period of 4.9 days, and as such contains no star considered old enough to have been the nebular progenitor. This represents a major challenge not only to current theories linking PN and binary star evolution, but also to standard theories of intermediate-mass stellar evolution.

In April 2005, as part of a continuing programme to study the morphology and kinematics of PNe with known close-binary central stars, spatially- resolved high-resolution longslit profiles of SuWt 2 were acquired using EMMI on the ESO-NTT. Here, I present the analysis of these position-velocity (PV) arrays, and the subsequent spatio-kinematic modelling performed in an attempt to replicate these results in synthetic spectra, hence determining the nebular morphology of SuWt 2. I will also discuss my findings in relation to the A-type binary and, most importantly, the various evolutionary scenarios that have been put forward for SuWt 2.

Slides: PDF

Date: 1 April (Wed) Time: 11:00am Place: 6th floor meeting room, Mayantigo building
Title: LUCIFER - the LBT NIR spectroscopic Utility with Camera and Integral-Field Unit for Extragalactic Research
Speaker (Affiliation): Jochen Heidt (ZAH, Landessternwarte Heidelberg, Germany)
Abstract: LUCIFER is a NIR spectrograph and imager (wavelength range 0.9 to 2.5 micron) for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona, working at cryogenic temperatures of less than 70K. Two instruments are built by a consortium of five German institutes and will be mounted at the bent Gregorian foci of the two individual telescope mirrors. Three exchangable cameras are available for imaging and spectroscopy: two of them are optimized for seeing-limited conditions, a third camera for the diffraction limited case will be used with the LBT adaptive secondary mirror working. Up to 33 exchangeable masks are available for longslit or multi-object spectroscopy (MOS) over the full field of view. At present, the commissioning of the first LUCIFER instrument at the LBT is almost complete. In this talk, I will give an overview about the LBT organisation and the operation of the LBT followed by an description of the instrument and the first results obtained during commissioning.

Date: 20 March (Friday) Time: 10:00am Place: 6th floor meeting room, Mayantigo building
Title: Young stars in Lupus: not as expected, not where expected
Speaker (Affiliation): Fernando Comeron (ESO)
Abstract: Most studies of the stellar and substellar populations of star forming regions rely on the identification of the signatures of accretion, outflows, circumstellar dust or activity characteristic of the early stages of stellar evolution. However, the decay of these observational signatures with time limits our ability to understand the complete star forming history of young aggregates, and to obtain unbiased samples of young stellar objects at different stages of disk evolution.

I will present the results of a wide-area study of the stellar population of selected clouds in the nearby Lupus star forming region, initially defined to complement the data obtained by the Spitzer Space Observatory Legacy Program "From molecular cores to planet-forming disks". When combined with 2MASS photometry, our data allow us to fit the spectral energy distributions of well over 150,000 sources seen in that direction, and to identify possible new members based on their photospheric fluxes alone, with independence of the display of signposts of youth. In this way we identify a very clear signature of the existence of a surprisingly numerous and thus far unrecognized population of cool members of Lupus 1 and 3, which is absent from Lupus 4.

The approximately 130 new members that we identify show that Lupus 1 and 3 have been forming low mass stars in numbers comparable to, or even exceeding in Lupus 1, those revealed by recent sensitive surveys based on the signposts of youth. We hypothesize on several possibilities for the origin of this population that may account for its puzzling properties of general lack of disks, coevality with the disk-bearing population, and preferential off-cloud location, which hint at a picture more complex and interesting than the quiescent formation inside dense molecular clouds.

Presentation: PPT | PDF

Date: 9 March (Monday) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: A rate study of Type Ia supernovae with Subaru/XMM-Newton Deep Survey
Speaker (Affiliation): Yutaka Ihara (Institute of Astronomy, University of Tokyo, Japan)
Abstract: I will talk about my study, a measurement of the rate of high-z Type Ia supernovae (SNe Ia) using multi-epoch observations of Subaru/XMM-Newton Deep Field (SXDF) with Suprime-Cam on the Subaru Telescope. Although SNe Ia are regarded as a standard candle, progenitor systems of SNe Ia have not been resolved yet. One of the key parameters to show the progenitor systems by observations is the delay time distribution between the binary system formation and subsequent SN explosion. Recently, a wide range of delay time is studied by SN Ia rates compared with an assumed cosmic star formation history. If SNe Ia with short delay time are dominant, the cosmic SN Ia rate evolution should closely trace that of the cosmic star formation. In order to detect a lot of high-z SNe Ia, we repeatedly carried out wide and deep imaging observations in the i-band with Suprime-Cam in 2002 (FoV~1 deg^2, m_i<25.5 mag). We obtained detailed light curves of the variable objects, and 50 objects are classified as SNe Ia using the light curve fitting method at the redshift range of 0.2
Presentation: PPT

Date: 17 Feb (Tuesday) Time: 12:00 Place: Fundación Galileo Galilei; Rambla José Ana Fernández Pérez, 7; Breña Baja
Title: Globular Clusters - Some simple, some complicated, all interesting!
Speaker (Affiliation): Alistair Walker, (Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory)
Abstract: Galactic globular clusters have for several decades been highly useful as examples of single stellar populations of stars almost as old as the Universe, and as such have been critical to calibrating models of stellar evolution for low mass stars, and for understanding galaxy formation and evolution. However, explanations for puzzles such as differing distributions of stars on the Horizontal Branch, and element-element abundance anomalies in individual clusters, have been elusive. Recent, mostly HST-ACS, observations of some globular clusters have complicated the picture but also give strong clues for resolving the remaining issues. After a short overview, I will describe a wide-field imaging program for a selected sample of clusters designed to provide complementary information to the HST and spectroscopic studies, and show some of the first results.

Date: 13 Feb (Friday) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Status and Plans for the ASTRONET Initiative
Speaker (Affiliation): Johannes Andersen (NOT & ASTRONET Board)
Abstract: The ASTRONET consortium aims to establish a comprehensive, long-term planning for all of European astronomy. Three years old, it has matured substantially: Nearly all significant European communities are involved; the Science Vision and Infrastructure Roadmap have been completed and published; and we are moving into the phase of implementing their recommendations. The talk will summarise the current status of ASTRONET and outline some of the options for the future.

Seminars in 2008

Date: 8 Jul (Tuesday) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Astronomy in real time
Speaker (Affiliation): Tiina Liimets (Tartu Observatory and ING)
Abstract: The objects of our project: the light echo of V838 Monocerotis, nova remnant GK Persei, nebulosities of R Aquarii, are exceptional stellar outflows which give as a very rare opportunity in astronomy to investigate the structure and kinematics of circumstellar matter in real time. For that we analyze the multi epoch images which are able to resolve the apparent expansion of the outflows, and thus provide the information of the velocity component in the plane of sky. This allows a detailed dynamical and morphological study to understand the geometry and physics of the ejection, outflows or light echoes.

Date: 8 Jul (Tuesday) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: Who is this girl and what is she doing here?
Speaker (Affiliation): Sarah Barker (University of Sheffield and ING)
Abstract: As part of my masters degree in Physics and Astrophysics with the University of Sheffield, I was lucky enough to be given the opportunity to apply to spend my final year here at the ING. For the past 10 months I have been working as a Support Astronomer at the Isaac Newton Telescope, whilst simultaneously studying for my degree. This talk gives an overview of the work I have done, and projects I have been involved with during this time.

Particular attention is paid to Broad Absorption Line Quasars, my main research interest this year. By using the level of ionisation of these BAL QSOs, I have estimated the distance to which high-velocity outflows extend from the centre of these quasars, and the results will be discussed in this talk.

Presentation: PPT

Date: 8 Jul (Tuesday) Time: 15:00 Place: 6th floor meeting room, Mayantigo building
Title: ARCS: the Asiago Red Clump Spectroscopic Survey and its applications
Speaker (Affiliation): Marica Valentini (Astronomical Observatory of Padova and ING)
Abstract: My PhD project is about a further investigation and characterization of local Red Clump Stars, in order to use them as distance indicators and tracers of Milky Way structure and kinematics. The project started in 2006 with ARCSs (Asiago Red Clump Spectroscopic survey), and then it will be fulfilled with data from Rave survey.

Now ARCS survey is ended, and I personally observed about 500 local Red Clump stars with the Echelle spectrograph, mounted in the Asiago 1.82m telescope. The data reduction and analisys ended in these days, at last. The result of this work will be the publication of one of the biggest Red Clump stars catalogue, containing radial velocities and atmospherical parameters of the selected sample. The analysis of this data also led to a calibration of a reliable function of Mv dependent on [M/H], log(g) and Teff, useful for using RC stars as distance indicators.

In the next future my project will continue with the application of the ARCSs and Rave data on classical problems of Milky Way structure and cinematics, as streams detection, local velocity escape calculation and detection of dark matter.


Date: 16 Apr (Wednesday) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: AGN feedback in compact radio sources
Speaker (Affiliation): Joanna Holt (Sterrewacht Leiden)
Abstract: Over the last decade or so, it has become clear that AGN feedback plays a key role in galaxy evolution. However, due to the lack of observational results, feedback is often inserted into the models as a black box. Theroetical analyses by e.g. Silk & Rees and Fabian give good descriptions of the feedback process, although these scenarios assume the feedback process is dominated by quasar-induced winds. Whilst this may be true for radio-quiet AGN, in radio-loud AGN the expanding radio jets may also provide a significant contribution to the overall feedback of the AGN.

In this talk I will discuss our recent study of the emission line outflows in compact radio sources. Compact radio sources are ideal objects in which to study AGN feedback as i) the compact radio source highlights the presence of a young, recently triggered AGN which still retains it's natal cocoon and ii) these sources contain all of the possible outflow driving mechanisms (AGN winds/starburst winds/radio jet activity) and are therefore the only objects in which the relative importance of all of the different feedback effects can be studied.

Slides: PPT Additional material: movie and movie player

Date: 27 Mar (Thursday) Time: 16:00 Place: 6th floor meeting room, Mayantigo building
Title: Galaxy formation - the fossil record of nearby stars
Speaker (Affiliation): Klaus Fuhrmann (ING)
Abstract: High-resolution spectroscopy of nearby solar-type stars implies that the Galaxy became reality 13 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years. In a second phase, the thin disk -- our "familiar Milky Way" -- came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter and that particularly challenge the hierarchical cold-dark-matter-dominated formation picture for our parent spiral.
Slides: Tar file

Date: 19 Mar (Wed) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: Galaxies with star-forming satellites: How typical is the Milky Way system?
Speaker (Affiliation): Phil James (Astrophysics Research Institute at Liverpool John Moores University)
Slides: PPT | PDF

Date: 13 Mar (Thursday) Time: 12:00 Place: 6th floor meeting room, Mayantigo building
Title: Sigma Orionis: A New Hope
Speaker (Affiliation): José A. Caballero (Universidad Complutense de Madrid)
Abstract: The sigma Orionis cluster is very young (about 3 My) and relatively nearby (a bit less than 400 pc). It takes the name from the Trapezium-like star system sigma Ori, which illuminates the mane of the Horsehead Nebula and is the fourth brightest star in the Orion Belt. The cluster is a well-equiped laboratory to investigate the stellar and substellar formation. It contains OB-type stars, Herbig-Haro objects, strong X-ray sources, peculiar multiple systems, Class I object candidates, highly photometric variable brown dwarfs, and the largest known population of isolated planetary-mass objects. I will give a general review on the sigma Orionis cluster, describing from the O9.5V star in its centre (M ~ 18 M_sun), to S Ori 70, that is to date the less-massive isolated body directly imaged out of the Solar System (M ~ 3 M_Jup).
Slides: PPT

Date: 18 Feb (Monday) Time: 12:00 Place: Meeting room, Fundación Galileo Galilei (Rambla José Ana Fernández Pérez, 7; San Antonio - Breña Baja)
Title: CTIO and the US System of Telescopes
Speaker (Affiliation): Alistair Walker (CTIO, NAO)
Abstract: I will describe the present status of the telescopes and instrumentation at CTIO, and then explain how the US National Optical Observatories (CTIO, KPNO) plan to evolve over the next decade, in the face of the competing demands of the new 'super projects' for both funding and support observations. This has led to the concept of the 'US System of Telescopes', designed to optimize the range of facilities available for US astronomers.
Slides: PDF | PPT

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Last modified: 09 April 2020