X-Ray Weak AGNs from Super-Eddington Accretion onto Infant Black Holes

Document detail

ID

oai:arXiv.org:2410.00417

Topic

Astrophysics - Astrophysics of Gal... Astrophysics - Cosmology and Nonga... Astrophysics - High Energy Astroph...

Author

Madau, Piero Haardt, Francesco

Year

2024

listing date

11/13/2024

Keywords

super-eddington astrophysics

Metrics

Abstract

A simple model for the X-ray weakness of JWST-selected broad-line AGNs is proposed under the assumption that the majority of these sources are fed at super-Eddington accretion rates.

In these conditions, the hot inner corona above the geometrically thin disk that is responsible for the emission of X-rays in "normal" AGNs will be embedded instead in a funnel-like reflection geometry.

The coronal plasma will Compton upscatter optical/UV photons from the underlying thick disk as well as the surrounding funnel walls, and the high soft-photon energy density will cool down the plasma to temperatures in the range 30-40 keV.

The resulting X-ray spectra are predicted to be extremely soft, with power-law photon indices Gamma=2.8-4.0, making high-z super-Eddington AGNs largely undetectable by Chandra.

;Comment: 7 pages, 4 figures, matches version accepted for publication in The Astrophysical Journal Letters

Madau, Piero,Haardt, Francesco, 2024, X-Ray Weak AGNs from Super-Eddington Accretion onto Infant Black Holes