The cosmic web of X-ray active galactic nuclei seen through the eROSITA Final Equatorial Depth Survey (eFEDS)

¹ Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstrasse 1, 85748 Garching bei München, Germany
e-mail: comparat@mpe.mpg.de
² Key Laboratory for Research in Galaxies and Cosmology, School of Astronomy and Space Science, University of Science and Technology of China, Hefei, Anhui, 230026 PR China
³ Department of Astronomy, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui, 230026 PR China
⁴ The Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune, 411007 India
⁵ Kavli Institute for the Physics and Mathematics of the Universe (IPMU), 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8583 Japan
⁶ Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
⁷ Instituto de Astronomía sede Ensenada, Universidad Nacional Autónoma de México, Km 107 Carretera Tijuana-Ensenada, 22860 Ensenada, Mexico
⁸ Department of Astronomy and Astrophysics, 525 Davey Lab., The Pennsylvania State University, University Park, PA, 16802 USA
⁹ Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA, 16802 USA
¹⁰ Department of Physics, 104 Davey Laboratory, The Pennsylvania State University, University Park, PA, 16802 USA
¹¹ Institute for Astronomy and Astrophysics, National Observatory of Athens, V. Paulou & I. Metaxa, Athens, 11532 Greece
¹² Astronomical Institute, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai, Japan
¹³ Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, 277-8583 Kashiwa, Tokyo, Japan
¹⁴ Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033 Japan
¹⁵ Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime, 790-8577 Japan
¹⁶ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 Japan
¹⁷ Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto, 606-8502 Japan
¹⁸ Academia Sinica Institute of Astronomy and Astrophysics, 11F Astronomy-Mathematics Building, AS/NTU, No. 1, Section 4, Roosevelt Road, Taipei, 10617 Taiwan
¹⁹ Department of Economics, Management and Information Science, Onomichi City University, Hisayamada 1600-2, Onomichi, Hiroshima, 722-8506 Japan
²⁰ Astronomy Department, University of Washington, Box 351580, Seattle, WA, 98195 USA
²¹ The Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA, 91101 USA

Received: 19 December 2022
Accepted: 21 March 2023

Abstract

Which galaxies in the general population turn into active galactic nuclei (AGNs) is a keystone of galaxy formation and evolution. Thanks to SRG/eROSITA’s contiguous 140 square degree pilot survey field, we constructed a large, complete, and unbiased soft X-ray flux-limited (F_X > 6.5 × 10⁻¹⁵ erg s⁻¹ cm⁻²) AGN sample at low redshift, 0.05 < z < 0.55. Two summary statistics, the clustering using spectra from SDSS-V and galaxy-galaxy lensing with imaging from HSC, are measured and interpreted with halo occupation distribution and abundance matching models. Both models successfully account for the observations. We obtain an exceptionally complete view of the AGN halo occupation distribution. The population of AGNs is broadly distributed among halos with a mean mass of 3.9_−2.4^+2.0 × 10¹² M_⊙. This corresponds to a large-scale halo bias of b(z = 0.34) = 0.99_−0.10^+0.08. The central occupation has a large transition parameter, σ_log10(M) = 1.28 ± 0.2. The satellite occupation distribution is characterized by a shallow slope, α_sat = 0.73 ± 0.38. We find that AGNs in satellites are rare, with f_sat < 20%. Most soft X-ray-selected AGNs are hosted by central galaxies in their dark matter halo. A weak correlation between soft X-ray luminosity and large-scale halo bias is confirmed (3.3σ). We discuss the implications of environmental-dependent AGN triggering. This study paves the way toward fully charting, in the coming decade, the coevolution of X-ray AGNs, their host galaxies, and dark matter halos by combining eROSITA with SDSS-V, 4MOST, DESI, LSST, and Euclid data.