Foreword

It gives me great pleasure to write a few words on behalf of the Joint Steering Committee as an introduction to this biennial report of the Isaac Newton Group of telescopes. The two years that this report covers have seen the ING produce results which have advanced astronomical research across a very broad front. Some of the highlights are detailed later in these pages.

In extragalactic astronomy we have seen the telescopes being used to perform some of the deepest ground-based surveys of the distant universe yet attempted. Our knowledge of galaxy evolution has been furthered by the discovery of a radio galaxy at z=4.41, observations of a lensed star-forming galaxy at z=2.515 and the observational determination that dwarf irregulars are old systems.

Many of the programmes performed on the ING are international collaborations using several telescopes. Of particular note is the WENSS survey which has been performed under international collaborative time using all three ING telescopes to follow up sources detected in the low-frequency Westerbork radio survey.

In the area of star formation and stellar evolution, the INT has been used to determine the relationship between spiral structure, star formation rate and the IMF in spiral galaxies. The results clearly show a bimodal IMF, favouring a larger fraction of massive stars in the arms than in the inter-arm regions. At the other end of the stellar mass scale, optical spectroscopy and infrared photometry with the WHT helped provide conclusive proof that the object Teide 1 is indeed a brown dwarf star, the first to be unambiguously identified. Since this important discovery, several more candidates have been detected using the INT. Again, this programme was conducted using international time.

The event that caught the imagination of the public more than any other during this period was undoubtedly the apparition of comet Hale-Bopp. Again, all three telescopes were used to obtain spectroscopic and imaging data. Spectrophotometry was used to probe the outgassing rate of molecules confirming that in Hale-Bopp this was particularly high. Imaging from the JKT helped to identify 6 jets emanating from the nucleus which were the source of much of the ejected material.

Operationally, the ING has continued to improve its service to astronomers. Down-time due to faults was well below 3% on all three telescopes (compared to the recognised target of 5%). Technical down-time may be reduced still further if the promising results of the CO₂ snow cleaning technique do indeed lead to less frequent re-aluminising of telescope primary mirrors.  Improvements to the working environment have also been made, and the long-awaited sea-level base is now operational. The programme of seeing and heat source evaluation has continued and has led to real gains in terms of deliverable image quality.
A primary goal we all share is to keep the ING internationally competitive. A vital part of this is the provision of new instrumentation. Thus the report contains details of the commissioning of several new instruments including WHIRCAM, MARTINI-3, Autofib/WYFFOS, the Tokyo Mosaic Camera and MUSICOS. In addition, there is a continuous  programme of instrument upgrades.

Finally, on behalf of the JSC, I would like to congratulate all the staff of the ING for their efforts in helping to make 1995 and 1996 such successful years, against a background of increasing financial pressures and uncertainty, and in particular Dr Rene Rutten for the  production of this excellent report.
 

Professor Mike Bode, Chairman of the Joint Steering Committee