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Self-consistent population synthesis of AGN from observational constraints in the X-rays

D Gerolymatou, S Paltani, C Ricci… - arXiv preprint arXiv …, 2025 - arxiv.org
Astrophysics paper astro-ph.CO Suggest

… We examine how well each model can match all observational constraints using a simulation-based inference (SBI) approach. We find that, while the simple unification …

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BibTeX

@article{2506.14885v1,
Author        = {D. Gerolymatou and S. Paltani and C. Ricci and M. Regamey},
Title         = {Self-consistent population synthesis of AGN from observational
  constraints in the X-rays},
Eprint        = {2506.14885v1},
DOI           = {10.1051/0004-6361/202553878},
ArchivePrefix = {arXiv},
PrimaryClass  = {astro-ph.CO},
Abstract      = {The cosmic X-ray background (CXB) is produced by the emission of unresolved
active galactic nuclei (AGN), thus providing key information about the
properties of the primary and reprocessed X-ray emission components of the AGN
population. Equally important, studies of individual sources provide additional
constraints on the properties of AGN, such as their luminosity and obscuration.
Until now, these constraints have not been self-consistently addressed by
intrinsically linking emission, absorption, and reflection. Here we perform
numerical simulations with the ray-tracing code, RefleX, which allows us to
self-consistently model the X-ray emission of AGN with flexible geometries for
the circumnuclear medium. Using the RefleX-simulated emission of an AGN
population, we attempt to simultaneously reproduce the CXB and absorption
properties measured in the X-rays, namely the observed fraction of
$N_{\mathrm{H}}$ in bins of log($N_{\mathrm{H}}$) and the fraction of absorbed
AGN, including their redshift and luminosity evolution. We sample an intrinsic
X-ray luminosity function and construct gradually more complex physically
motivated geometrical models. We examine how well each model can match all
observational constraints using a simulation-based inference (SBI) approach. We
find that, while the simple unification model can reproduce the CXB, a
luminosity dependent dusty torus is needed to reproduce the absorption
properties. When adding an accretion disc, the model best matches all
constraints simultaneously. Our synthetic population is able to reproduce the
dependence of the covering factor on luminosity, the AGN number counts from
several surveys, and the observed correlation between reflection and
obscuration. Finally, we derive an intrinsic Compton-thick fraction of
21$\pm$7%, consistent with local observations.},
Year          = {2025},
Month         = {Jun},
Note          = {A&A 700, A252 (2025)},
Url           = {http://arxiv.org/abs/2506.14885v1},
File          = {2506.14885v1.pdf}
}

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