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What can be learnt from extragalactic X-ray surveys?

✍ Scribed by A.C. Fabian


Publisher
John Wiley and Sons
Year
2003
Tongue
English
Weight
129 KB
Volume
324
Category
Article
ISSN
0004-6337

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✦ Synopsis


Abstract

Extragalactic X‐ray surveys reveal many Active Galactic Nuclei (AGN) as well as clusters and groups of galaxies. Many of the AGN are obscured, leading to the hard spectrum of the X‐ray Background. Constraints from the absorptioncorrected X‐ray Background spectrum and the local mass density of black holes on the radiative efficiency and growth of accreting black holes are discussed. The use of clusters for the determination of cosmological parameters, and the energy and metallicity loss by galaxies and AGN, is noted.