Hard X-Ray Emission from Elliptical Galaxies and Its Contribution to the X-Ray Background
Open Access
- 10 December 1999
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 527 (1) , L21-L24
- https://doi.org/10.1086/312387
Abstract
We explore the implications of the discovery of hard, power-law X-ray sources in the spectra of nearby elliptical galaxies for the origin of the X-ray background (XRB). The spectra of these sources are consistent with models of thermal bremsstrahlung emission from low radiative efficiency accretion flows around central supermassive black holes and are unique in that they approximately match the spectrum of the hard XRB. If such sources, with luminosities consistent with those observed in nearby elliptical galaxies, are present in most early-type galaxies, then their integrated emission may contribute significantly to the XRB. These sources may also contribute to the hard source counts detected in deep X-ray surveys.Keywords
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