The Lockman-SpReSO Project: A Deep X-ray Spectral View of a FIR-selected AGN Population
Abstract We present a detailed X-ray spectral analysis of the active galactic nucleus (AGN) population in the Lockman-SpReSO project, a multiwavelength campaign of FIR sources in the Lockman Hole field. Using deep XMM-Newton observations cross-matched with FIR-selected galaxies, we characterize 94 AGNs based on their X-ray spectral properties. The sample is distributed over a large redshift range of z = 0.07 − 5, and reaches a flux limit of 5 × 10−16 erg s−1 cm−2 in the 0.3 − 10 keV band. We model the X-ray spectra using absorbed power-law, reflection, and soft excess components to estimate intrinsic column densities (NH), rest-frame 2 − 10 keV luminosities, and iron line equivalent widths (EW). Additionally, we included an advanced model fitting for Compton-thick AGNs (CT-AGNs) using the XCLUMPY model. Our results show an increase in the fraction of obscured AGNs toward higher redshifts, including the identification of one strong and two borderline CT-AGN candidates with NH ≳ 1024 cm−2. Soft excess emission is detected in 10 AGNs, with an average blackbody temperature of 0.12 ± 0.02 keV. We also detect the X-ray Baldwin effect in both obscured and unobscured populations, and we found a strong correlation between the torus angular width (σtor), dust covering factor (fcov), and X-ray luminosity, described by fcov = ( − 0.1 ± 0.01) × log (L2 − 10 keV/(1044 erg s−1)) + (0.65 ± 0.01), supporting the receding torus scenario. While consistent with deep X-ray surveys, the FIR selection favours the identification of dusty star-forming host galaxies and heavily obscured AGNs.
Authors
- Á. Bongiovanni (ORCID: https://orcid.org/0000-0002-3557-3234)
- C. A. Negrete (ORCID: https://orcid.org/0000-0002-1656-827X)
- J. Cepa (ORCID: https://orcid.org/0000-0002-6566-724X)
- M. Cerviño (ORCID: https://orcid.org/0000-0001-8009-231X)
- Y. Krongold (ORCID: https://orcid.org/0000-0001-6291-5239)
- M. Rodríguez (ORCID: https://orcid.org/0000-0001-7970-4809)
- M. Elías-Chávez (ORCID: https://orcid.org/0000-0002-0115-8374)
- Jose Antonio Vazquez Mata
- E. Benítez (ORCID: https://orcid.org/0000-0003-1018-2613)
- V. Ávila-Reese (ORCID: https://orcid.org/0000-0002-3461-2342)
- M. Pović (ORCID: https://orcid.org/0000-0002-9766-6110)
- T. Miyaji (ORCID: https://orcid.org/0000-0002-7562-485X)
- E. J. Alfaro (ORCID: https://orcid.org/0000-0002-2234-7035)
- I. Cruz-González (ORCID: https://orcid.org/0000-0002-2653-1120)
- Carmen P. Padilla-Torres (ORCID: https://orcid.org/0000-0001-5475-165X)
- M. Herrera-Endoqui (ORCID: https://orcid.org/0000-0002-8653-020X)
- Mauro González-Otero (ORCID: https://orcid.org/0000-0002-4837-1615)
- Bereket Assefa
- M Sánchez-Portal
- Héctor Hernández-Toledo
- J Ignacio González-Serrano
- J Jesús González
- A M Perez Garcia
- J Antonio de Diego
Institutions
- Debre Berhan University (ET)
- Mbarara University of Science and Technology (UG)
- Universidad de La Laguna (ES)
- Universidad Autónoma de la Ciudad de México (MX)
- Asociación para la Conservación de la Cuenca Amazónica (PE)
- Ethiopian Space Science and Technology Institute (ET)
- Centro de Astrobiología (ES)
- Instituto de Astrofísica de Canarias (ES)
- Instituto de Radioastronomía Milimétrica (ES)
- Instituto de Física de Cantabria (ES)
- Instituto de Astrofísica de Andalucía (ES)
- Telescopio Nazionale Galileo (ES)
- Universidad Nacional Autónoma de México (MX)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2026-07-01
- DOI
- https://doi.org/10.1093/mnras/stag1248
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 0.00