CLUSTERS of galaxies are the largest gravitationally bound systems in the Universe and therefore provide important constraints on the formation and evolution of large-scale structure. Cluster evolution can be inferred from observations of the X-ray emission of the gas in distant clusters, but interpreting these data is not straightforward. In a

Using a 2D generalization of Kent's model-independent decomposition method, we extract the K-band light profiles of the bulges of a sample of field galaxies with morphological types ranging from S0 to Sbc. We then examine the shape of the bulge profiles, by means of fitting a seeing-convolved power law of the form μ(r) is proportional to r^1/n^

We present intermediate resolution spectroscopy of the dwarf nova CY UMa in quiescence. From the radial velocities of the Hα emission, we derive an orbital period of 0.067 95+/-8x10^-5 d, which disagrees with previous photometric estimates. We also constrain the system parameters. The core of the Hα emission seems to be dominated by a component

T Tauri, the prototype of a class of low-mass pre-main sequence stars, was observed with the 3.6m Canada-France-Hawaii telescope (CFHT) and the CP40 photon-counting camera in November 1989. The data have been analysed using techniques of Speckle Interferometry to obtain diffraction-limited information on the spatial extent of T Tauri in narrow

To investigate the distribution of dust in Sb and Sc galaxies we have analyzed near-infrared and optical surface photometry for an unbiased sample of 37 galaxies. Since light in the K-band is very little affected by extinction by dust, the B - K colour is a good indicator of the amount of extinction, and using the colour-inclination relation we can

We present stellar population models for starbursts in a sample of eleven Wolf-Rayet galaxies. Taking into account the observational data available, we try to reconstruct the number of Wolf-Rayet stars observed and estimate the number of type II supernovae that have exploded in the ionizing cluster. Using the stellar yields of the most recent