BX And is such a system: orbital period changes indicate mass transfer 4×10^-8 solar masses per year, and variable light curves can be explained by a hotspot located symmetrically about the line of centres covering about 20% of the secondary, perhaps a mass of gas floating on the secondary during the initial stages of transfer. Variations in the period are probably due to changes in the mass transfer rate, which also have an effect on the size and temperature of the hotspot and hence on the shape of the light curve. Once into contact, these systems continue to display enhanced magnetic activity in the form of starspots and active chromospheres, as demonstrated by recent INT observations of AG Vir and SS Ari.
 

Using the Multipurpose Fotometer mounted on the JKT, researchers observed several eclipses of the eclipsing cataclysmic variable UX Uma in four wavebands and reconstructed the accretion disk structure using a maximum-entropy technique. The reconstruction shows that the bulk of the optical radiation comes from a more or less symmetric structure centered on the white dwarf, but that there is also a smaller spot, where the gas stream from the cool star hits the accretion disc.
AM Her systems are an important class of cataclysmic variables in which the secondary star loses material to a strongly magnetic white dwarf primary. The magnetic field on the primary is enormously strong, some tens of megagauss, so that the stream of material does not form a disk, but is captured by the field, and accretes on to the white dwarf in one or more shock regions at the magnetic poles. The energy of the system is released partly as X-rays in the shocks, and partly as optical cyclotron radiation from free electrons in the stream spiralling in the magnetic field. This radiation is emitted at low-order harmonics of the fundamental cyclotron frequency, broadened into humps by Doppler motion of the electrons in the emission region. Observing these humps in the spectra of AM Her systems is very difficult, but some reseachers using the WHT Faint Object Spectrograph were able to detect humps in a total of five systems. From the observations it is possible to determine the magnetic field strengths and temperatures of the emitting regions. The fields lie between 25 and 44 megagauss and the estimated temperatures lie between 5.0 and 23 keV. The data are now subject to detailed modelling.
 

There are now 20 quasars known above a redshift of z=4, seven of which have had their nature and redshift confirmed using the INT. One third of the 36 highest known redshift quasars have been discovered by the ING.

Further problems with the Cold Dark Matter model were revealed in an analysis of large-scale galaxy clustering published recently. The researchers undertook an all-sky redshift survey of IRAS galaxies: 1211 new redshifts were obtained, the great majority with the WHT, with some from the INT and other telescopes. Other redshifts were obtained from the literarure or unpublished sources. The result was a uniform all-sky sample encompassing a larger volume of the Universe than any previous redshift survey and a map of the distribution of galaxies within a radius of 150h^-1 Mpc. A clustering analysis of this map showed that the variation in density of galaxies over the Universe is inconsistent with the predictions of the Cold Dark Matter model.

The same reseachers used the map of the distibution of galaxies on the Local Group of Galaxies, and deduce the corresponding perculiar motion of the Local Group. They found that the acceleration acting on the Local Group is generated by a dozen or so clusters within 100h^-1Mpc, and the velocity of the Local Group with respect to the microwave background radiation of 600 kms^-1 can be explained provided the Universe has a density close to the critical value. No additional clusters located behind the galactic plane are needed to account for the Local Group motion, and there is no very large structure behind the Centaurus cluster capable of generating the claimed streaming motions of 1000kms^-1, so the rationale for the 'Great Attractor' appears to have faded. 
 

An exposure lasting over three hours was made of an extremely faint arc structure around the central galaxy of the rich cluster Abell 963 (redshift z=0.206) in 0.8 arcsecond seeing, revealing a single strong emission line at a wavelength of 6600Å. The interpretation of this observation is that the imaged object is a very distant spiral galaxy containing regions of active star formation: the emission line is [OII] redshifted to z=0.771. A second arc in this cluster proved too faint for spectroscopy, but INT images showed that the two arcs have similar unusually blue colours, indicating that they are two gravitational images of the same object.
 

OTHER HIGHLIGHTS 

The globular cluster M15 is undergoing gravitational collapse and it has been a mystery as to how such clusters could survive this collapse. It is thought that this contraction could be halted through the formation of binary systems. The ISIS spectrograph and the WHT have been used to detect these binary systems and add weight to this theory. 

The INT has been used, with the Faint Object Spectrograph, to discover proto-planetary nebulae. The results showed high velocity stellar winds which had not previously been thought to form.