The contribution of AGNs to the X-ray background

TL;DR

This paper models the contribution of different AGN classes to the extragalactic X-ray background, fitting observational data across a wide energy range and assessing their relative contributions.

Contribution

It presents a unified model based on AGN unification schemes and recent spectral observations to explain the X-ray background.

Findings

AGN emission can account for most of the XRB from 5 to 100 keV.

The model explains about 74% of the ROSAT soft XRB.

Predictions align with observational constraints from surveys.

Abstract

We report the results of a detailed analysis of the contribution of various classes of AGNs to the extragalactic X-ray background (XRB). The model is based on the unification schemes of AGNs and on their related X-ray spectral properties in the light of recent observational results. The integrated emission from AGNs, when folded with an appropriate cosmological evolution law, can provide a good fit to the XRB over a wide energy range, from several to $\sim$ 100 keV, while it contributes only about 74\% of the ROSAT soft XRB. The model predictions have been checked against all available observational constraints from both hard and soft X-ray surveys (counts, redshift distributions and average X-ray source spectral properties).