Detection of Luminous Intracluster Extreme-Ultraviolet Emission From Abell 1795
Abstract
We have observed the rich cluster Abell 1795 for 90,000 s, using the deep survey telescope aboard the Extreme-Ultraviolet Explorer, with the Lex/B (69-190 eV) passband filter. Very luminous emission was detected, with a marked softening of the spectrum toward the limiting sensitivity radius of 10' (~0.67 Mpc, assuming here and thereafter a Hubble constant of 75 km s-1 Mpc-1), where the EUV intensity is 6 times higher than that expected from the low-energy tail of the thermal X-ray emission, and the resulting EUV luminosity (a model-independent quantity) exceeds that of the X-ray band. The consequence of a thermal model interpretation is the existence of a warm (sub-MK) intracluster gas that is dynamical (cooling times <=10-4 of a Hubble time) and that contains a significant fraction, perhaps all, of the total missing mass of the cluster. Alternative interpretations of the data also invoke assumptions that have significant ramifications in our understanding of clusters.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1998
- DOI:
- 10.1086/311295
- Bibcode:
- 1998ApJ...498L..17M
- Keywords:
-
- GALAXIES: CLUSTERS: GENERAL;
- GALAXIES: CLUSTERS: INDIVIDUAL NAME: ABELL 1795;
- X-RAYS: GALAXIES;
- Galaxies: Clusters: General;
- Galaxies: Clusters: Individual: Name: Abell 1795;
- X-Rays: Galaxies