X-ray emission from E and SO galaxies with compact nuclear radio sources.

The imaging proportional counter on the Einstein Observatory has been used to search for X-ray emission from 13 nearby E and S0 galaxies with compact nuclear radio sources. Five galaxies with X-ray luminosity of about 10 to the 41st ergs/s were detected, and one of them was resolved. These galaxies and a few similar ones observed by others are compared to a sample of radio-quiet E and S0 galaxies. The radio-emitting galaxies have consistently greater X-ray luminosities per unit of optical luminosity than most radio-quiet galaxies. Possible emission mechanisms and models for the resolved source, for the most powerful source, and for the class of E/S0 galaxies with active nuclei are discussed.