The diffuse X-ray background

Abstract

The deepest observations of the X-ray background approach the surface brightness of the truly diffuse component generated by Thomson scattering of cosmic X-ray photons. Available estimates of the electron density and the X-ray luminosity density of AGNs as a function of cosmological epoch are used to calculate the integral scattered X-ray background component. It is shown that the scattered component constitutes 1.0 - 1.7 % of the total background, depending on the AGN cosmic evolution. Albeit this is a minute fragment of the total flux, it becomes a perceptible fraction of the still unresolved part of the background and should be taken into account in the future rigorous assessments of the X-ray background structure. This diffuse component at energies < 1 keV sums up with the emission by WHIM to 3 - 4 %. Consequently, one should expect that integrated counts of discrete sources account for just 96 - 97 % for soft background and ~99 % at higher energies.

5 pages, 2 figures, AA in print

References in corpus (11)

• Where are the Baryons?
• Baryons in the Warm-Hot Intergalactic Medium
• The resolved fraction of the Cosmic X-ray Background
• Implications of WMAP Observations On the Population III Star Formation Processes
• Hydrodynamic Simulation of the Cosmological X-ray Background
• A deep ROSAT survey - IV. The evolution of X-ray-selected QSOs
• The phase-diagram of cosmological baryons
• Origin of the X-Ray Background and AGN Unification: New Perspectives
• The deepest X-ray look at the Universe
• The X-ray surface brightness distribution from diffuse gas
• Missing baryons and the soft X-ray background

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• Can the unresolved X-ray background be explained by emission from the optically-detected faint galaxies of the GOODS project?
• Constraints on the Redshift Evolution of the L_X-SFR Relation from the Cosmic X-Ray Backgrounds
• Cosmic and Galactic Neutrino Backgrounds from Thermonuclear Sources
• Upper Limit on Dimming of Cosmological Sources by Intergalactic Grey Dust from the Soft X-ray Background