Detection of Excess Hard X-Ray Emission from the Group of Galaxies HCG 62

From the group of galaxies HCG62, we detected an excess hard X-ray emissionin energies above $\sim 4$ keV with \A SCA. The excess emission is spatiallyextended up to $\sim10'$ from the group center, and somewhat enhanced towardnorth. Its spectrum can be represented by either a power-law of photon index0.8-2.7, or a Bremsstrahlung of temperature $>6.3$ keV. In the 2-10 keV range,the observed hard X-ray flux, $(1.0\pm0.3)\times10^{-12}$ erg cm$^{-2}$s$^{-1}$, implies a luminosity of $(8.0\pm2.0)\times10^{41}$ erg s$^{-1}$ for aHubble constant of 50 km s$^{-1}$ Mpc$^{-1}$. The emission is thus too luminousto be attributed to X-ray binaries in the memb er galaxies. We discuss possibleorigin of the hard X-ray emission.Comment: 6 pages, 3 Postscript figures, uses emulateapj.sty. Accepted for publication in the Astrophysical Journal Letter