X-ray emitting gas, cooling flows and stellar populations in elliptical galaxies

The thesis concerns x-ray emitting gas, cooling flows and stellar populations in elliptical galaxies. X-ray surface brightness profiles of a large sample of clusters of galaxies are analysed using a method that makes no assumptions about the thermal distribution of the gas. Accurate radial density profiles for the gas are derived. Central cooling times and mass flow rates are also derived for the clusters in the sample. The x-ray emitting gas around the radio sources Cygnus-A and PKS 0745-191 are discussed, and both are shown to possess cooling flows. The consequences of cooling for observations in other wavelength regions are briefly reviewed. Infrared spectroscopy of the 2-3 μm CO absorption feature in a sample of standard stars, Galactic Bulge giants, normal elliptical galaxies and cooling flows are presented. Finally the relevance of cooling flows to other phenomena is discussed. (U.K.)