Constraining the AGN luminosity function from JWST with the X-ray Background

Abstract

We predict the X-ray background (XRB) expected from the population of quasars detected by the JWST spectroscopic surveys over the redshift range $z\sim 4-7$. We find that the measured UV emissivities, in combination with a best-fitting quasar SED template, imply a $\sim 10$ times higher unresolved X-ray background than constrained by current experiments. We illustrate the difficulty of simultaneously matching the faint-end of the quasar luminosity function and the X-ray background constraints. We discuss possible origins and consequences of this discrepancy.

arXiv comment6 pages, 4 figures; minor typos corrected, references updated. Matches version published in ApJL

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Cited by in corpus (3)

• Challenging the AGN scenario for JWST/NIRSpec LRD and non-LRD broad H$\alpha$ emitters in light of non-detection of NIRCam photometric variability and X-ray
• AGN ruled out as the dominant source of cosmic reionization
• Physical Processes Behind the Co-Evolution of Halos, Galaxies and Supermassive Black Holes in the IllustrisTNG Simulation