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Extended X-ray emission at high redshifts: radio galaxies versus clusters

A. Celotti·A. C. Fabian
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Abstract

Most old distant radio galaxies should be extended X-ray sources due to inverse Compton scattering of Cosmic Microwave Background (CMB) photons. Such sources can be an important component in X-ray surveys for high redshift clusters, due to the increase with redshift of both the CMB energy density and the radio source number density. We estimate a lower limit to the space density of such sources and show that inverse Compton scattered emission may dominate above redshifts of one and X-ray luminosities of 10^44 erg/s, with a space density of radio galaxies > 10^-8 Mpc^-3. The X-ray sources may last longer than the radio emission and so need not be associated with what is seen to be a currently active radio galaxy.

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A. Celotti, A. C. Fabian. 2004-05-31. Extended X-ray emission at high redshifts: radio galaxies versus clusters. https://doi.org/10.1111/j.1365-2966.2004.08085.x

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