English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

As matter accretes onto the central supermassive black holes in activegalactic nuclei (AGN), X-rays are emitted. We present a population synthesismodel that accounts for the summed X-ray emission from growing black holes;modulo the efficiency of converting mass to X-rays, this is effectively arecord of the accreted mass. We need this population synthesis model toreproduce observed constraints from X-ray surveys: the X-ray number counts, theobserved fraction of Compton-thick AGN [$\log$ (N$_{\rm H}$/cm$^{\rm -2}$) $>$24] and the spectrum of the cosmic X-ray background (CXB), after accounting forselection biases. Over the past decade, X-ray surveys by {\it XMM-Newton}, {\itChandra}, \textit{NuSTAR} and \textit{Swift}-BAT have provided greatly improvedobservational constraints. We find that no existing X-ray luminosity function(XLF) consistently reproduces all these observations. We take the uncertaintyin AGN spectra into account, and use a neural network to compute an XLF thatfits all observed constraints, including observed Compton-thick number countsand fractions. This new population synthesis model suggests that,intrinsically, 50$\pm$9\% (56$\pm$7\%) of all AGN within z $\simeq$ 0.1 (1.0)are Compton-thick.

The Accretion History of AGN I: Supermassive Black Hole Population Synthesis Model