| Title: |
Accretion properties of X-ray AGN: Evidence for radiation-regulated obscuration with redshift-dependent host galaxy contribution |
| Authors: |
Laloux B.; Georgakakis A.; Alexander D. M.; Buchner J.; Andonie C.; Acharya N.; Aird J.; Alonso-Tetilla A. V.; Bongiorno A.; Hickox R. C.; Lapi A.; Musiimenta B.; Almeida C. R.; Villforth C.; Shankar F. |
| Contributors: |
Laloux, B.; Georgakakis, A.; Alexander, D. M.; Buchner, J.; Andonie, C.; Acharya, N.; Aird, J.; Alonso-Tetilla, A. V.; Bongiorno, A.; Hickox, R. C.; Lapi, A.; Musiimenta, B.; Almeida, C. R.; Villforth, C.; Shankar, F. |
| Publication Year: |
2024 |
| Collection: |
International School for Advanced Studies (SISSA), Trieste: SISSA Digital Library (SDL) |
| Subject Terms: |
galaxies: acti ve –X-rays: g alaxies - infrared: g alaxies; Settore FIS/05 - Astronomia e Astrofisica |
| Description: |
We adopt a Bayesian X-ray spectral approach to investigate the accretion properties of unobscured (20 < log ( N H / cm −2 < 22) and obscured (22 < log ( N H / cm −2 < 24) active galactic nuclei (AGNs) to shed light on the orientation versus evolution scenarios for the origin of the obscuring material. For a sample of 3882 X-ray-selected AGN from the Chandra COSMOS Legacy, AEGIS, and CDFS extragalactic surveys, we constrain their stellar masses, M , intrinsic X-ray luminosities, L X , obscuring column densities, N H , and specific accretion rates λ∝ L X /M . By combining these observables within a Bayesian non-parametric approach, we infer, for the first time, the specific accretion rate distribution (SARD) of obscured and unobscured AGN to z ≈3, i.e. the probability of a galaxy with mass M at redshift z hosting an AGN with column density N H and specific accretion rate λ. Our findings indicate that (1) both obscured and unobscured SARDs share similar shapes, shifting towards higher accretion rates with redshift, (2) unobscured SARDs exhibit a systematic offset towards higher λcompared to obscured SARD for all redshift intervals, (3) the obscured AGN fraction declines sharply at log λbreak ∼−2 for z < 0 . 5, but shifts to higher λvalues with increasing redshift, (4) the incidence of AGN within the theoretically unstable blow-out region of the λ−N H plane increases with redshift. These observations provide compelling evidence for AGN ‘downsizing’ and radiation-regulated nuclear-scale obscuration with an increasing host galaxy contribution towards higher redshifts. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
info:eu-repo/semantics/altIdentifier/wos/WOS:001276911500012; volume:532; issue:3; firstpage:3459; lastpage:3479; numberofpages:21; journal:MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY; https://hdl.handle.net/20.500.11767/140790; https://arxiv.org/abs/2403.07109 |
| DOI: |
10.1093/mnras/stae1649 |
| Availability: |
https://hdl.handle.net/20.500.11767/140790; https://doi.org/10.1093/mnras/stae1649; https://arxiv.org/abs/2403.07109 |
| Rights: |
info:eu-repo/semantics/openAccess ; license:Creative commons ; license uri:http://creativecommons.org/licenses/by/4.0/ |
| Accession Number: |
edsbas.A1BEEBB4 |
| Database: |
BASE |