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Detection of Excess Hard X-ray Emission from the Group of Galaxies HCG62

Yasushi Fukazawa·Kazuhiro Nakazawa·Naoki Isobe·Kazuo Makishima·Kyoko Matsushita·Takaya Ohashi·Tsuneyoshi Kamae
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Abstract

From the group of galaxies HCG62, we detected an excess hard X-ray emission in energies above $\sim 4$ keV with \A SCA. The excess emission is spatially extended up to $\sim10'$ from the group center, and somewhat enhanced toward north. Its spectrum can be represented by either a power-law of photon index 0.8-2.7, 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 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 memb er galaxies. We discuss possible origin of the hard X-ray emission.

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Yasushi Fukazawa, Kazuhiro Nakazawa, Naoki Isobe, Kazuo Makishima, Kyoko Matsushita, Takaya Ohashi, Tsuneyoshi Kamae. 2000-11-14. Detection of Excess Hard X-ray Emission from the Group of Galaxies HCG62. https://doi.org/10.1086/318863

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