The X-ray morphology of the relaxed cluster of galaxies A 2256. II. Sources around the extended cluster emission.
Abstract
The X-ray observation of A2256 with the imaging proportional counter on board the X-ray observatory ROSAT revealed significantly more sources in the field around the extended cluster emission than one would expect by chance. In a preliminary investigation 14 sources were discovered at the limiting flux for this exposure whereas about 7 sources would have been expected by chance. At least two of those sources are coincident with cluster member galaxies, having X-ray luminosities of approximately 10^+42^ erg s ^-1^ in the ROSAT energy band from 0.1 to 2.4 keV, but at least four more are from `dark' objects. The similarity of these objects to those in A1367 suggests the existence of a new class of X-ray sources in clusters.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1991
- Bibcode:
- 1991A&A...246L..14H
- Keywords:
-
- Galactic Clusters;
- Galactic Radiation;
- Rosat Mission;
- X Ray Imagery;
- X Ray Sources;
- Brightness Distribution;
- Proportional Counters;
- Spaceborne Astronomy;
- Astrophysics