Detection of Excess Hard X-Ray Emission from the Group of Galaxies HCG 62
Abstract
We detected an excess of hard X-ray emission at energies above ~4 keV from the group of galaxies HCG 62 using data from the ASCA satellite. The excess emission is spatially extended up to ~10' from the group center and somewhat enhanced toward the north. Its spectrum can be represented by either a power law of photon index 0.8-2.7 or a bremsstrahlung of temperature greater than 6.3 keV. In the 2-10 keV range, the observed hard X-ray flux, (1.0+/-0.3)×10-12 ergs cm-2 s-1, implies a luminosity of (8.0+/-2.0)×1041 ergs s-1 for a Hubble constant of 50 km s-1 Mpc-1. The emission is thus too luminous to be attributed to X-ray binaries in the member galaxies. We discuss possible origins of the hard X-ray emission.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2001
- DOI:
- 10.1086/318863
- arXiv:
- arXiv:astro-ph/0011257
- Bibcode:
- 2001ApJ...546L..87F
- Keywords:
-
- Galaxies: Clusters: Individual: Alphanumeric: HCG 62;
- Galaxies: Evolution;
- X-Rays: Galaxies;
- Astrophysics
- E-Print:
- 6 pages, 3 Postscript figures, uses emulateapj.sty. Accepted for publication in the Astrophysical Journal Letters