The peak region of the extragalactic background radiation

TL;DR

This paper reviews the current understanding of the Cosmic X-ray background's peak, emphasizing recent measurements and the role of obscured AGNs, to better comprehend the population of Compton-thick AGNs and cosmic accretion processes.

Contribution

It provides a comprehensive review of recent measurements and advancements in understanding the Cosmic X-ray background and AGN populations, highlighting open issues and future directions.

Findings

Recent measurements refine the shape and intensity of the X-ray background.

Understanding AGNs helps constrain the population of obscured, Compton-thick AGNs.

Open issues remain in fully characterizing the AGN contribution to the background.

Abstract

The Cosmic X-ray background carries the information of cosmic accretion onto super-massive black holes. The intensity at its peak can be used to constrain the integrated space density of highly obscured AGNs. Determining the shape and intensity of the Cosmic X-ray background radiation represents, however, a first step towards the understanding of the population of Comptonthick AGNs. The study of AGNs in the local and more distant Universe allows to understand the whole picture. In this talk, I will review the current understanding of generation of the Cosmic X-ray background at its peak. I will focus on the recent measurements of the Cosmic X-ray background and I will discuss the recent advancements in the understanding of AGNs in both the local and more distant Universe. Finally, I will also discuss open issues and future prospects.