Properties of the X-ray emitting gas in early-type galaxies

The properties of the X-ray emitting gas in a sample of 81 E and S0 galaxies observed with the Einstein Observatory are studied. Measured fluxes for 55 of the galaxies and upper limits for 26 of them are reported. An attempt is made to use consistent optical parameters for the galaxies, including a correction to the velocities for the Virgocentric flow. The sample is then used to explore the contribution from discrete sources, the global physical properties of the hot gas, and the implications for heating by supernovae and gravity. Finally, the question of the presence of heavy halos is addressed.