Active galactic nuclei make the cosmic X-ray background

Abstract

view Abstract Citations (30) References (55) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Active Galactic Nuclei Make the Cosmic X-Ray Background Zdziarski, Andrzej A. ; Zycki, Piotr T. ; Krolik, Julian H. Abstract While it has long been know that active galactic nuclei (AGNs) make up a significant part of the X-ray background near 1 keV, it has been generally thought that the typical AGN X-ray spectrum did not fit the higher energy background spectrum. More recent data (from Ginga, SIGMA, and OSSE) show that the X-ray spectra of radio-quiet AGNs do in fact resemble the X-ray background spectrum. These data are well described (from 2 to 100 keV) by a model in which the X-ray photons are made by thermal Comptonization, and a fraction (around a half) of the X-rays are reflected by a cool surface. Using the observed evolution of X-ray-bright AGNs, we show that the known AGN population, radiating the spectrum observed at low redshift and integrated in redshift back to z ~ 4, is capable of producing the entire X-ray background from 2 to 100 keV. Publication: The Astrophysical Journal Pub Date: September 1993 DOI: 10.1086/187001 Bibcode: 1993ApJ...414L..81Z Keywords: Active Galactic Nuclei; Cosmic X Rays; Relic Radiation; Astronomical Spectroscopy; Quasars; Red Shift; Seyfert Galaxies; X Ray Spectra; Astrophysics; COSMOLOGY: DIFFUSE RADIATION; GALAXIES: ACTIVE; RADIATION MECHANISMS: MISCELLANEOUS; X-RAYS: GALAXIES full text sources ADS | data products SIMBAD (1)