Open AccessExtended X‐ray emission at high redshifts: radio galaxies versus clusters
Author(s) -
Celotti A.,
Fabian A. C.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08085.x
Subject(s) - physics , astrophysics , redshift , radio galaxy , astronomy , galaxy , galaxy cluster , galaxy groups and clusters
Most old, distant radio galaxies should be extended X‐ray sources because of inverse Compton scattering of cosmic microwave background (CMB) photons. Such sources can be an important component in X‐ray surveys for high‐redshift clusters, because of 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 1 and X‐ray luminosities of 10 44 erg s −1 , 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.