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   72173
   We will determine the contribution of X-ray binaries to the X-ray
   emission of early type galaxies and the importance of a group potential
   to gravitationally bind the hot gas, by extending the ASCA study of
   Virgo early-type galaxies to fainter optical magnitudes. We propose to
   observe NGC4526, NGC4621, NGC4473 and NGC4459. These, combined with
   archival observations, will provide a unique optically selected sample,
   which also can be used to study the effects of the cluster environment
   on the kT - Lx and Lx - Lopt relations, the Fe - kT dependence and to
   derive the Virgo Si/Fe - Fe relation.
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