Disentangling Stellar Mass and Environmental Effects on eROSITA AGN Activity using multi-wavelength data from GAMA, WISE, GALEX, and DESI Legacy Survey
Year: 2026
Type: preprint
Abstract: We use a stellar-mass complete sample of $\sim 36{,}000$ galaxies from GAMA/eFEDS to test whether AGN activity depends on environment independent of stellar mass. To isolate this effect, we introduce $δ_{\rm rank}$, a novel local overdensity metric defined within narrow stellar mass bins. Our main result is that X-ray-selected AGNs show a clear environmental trend, the AGN fraction rises from $\sim 4\%$ in low-density regions to $\sim 6\%$ in high-density regions, with a sharp transition at $δ_{\rm rank} \sim 0.4$. This environmental dependence is absent for WISE-selected and broad-line AGN, and Eddington ratios show no variation across environments. We also found that for galaxies with $\mathrm{SFR} > 15\,M_\odot\,\mathrm{yr}^{-1}$, X-ray AGN fraction is approximately 5%, 60% and 20% in low, mid and high $δ_{\rm rank}$ galaxies. We show that relationship between AGN fraction and SFR varies dramatically with both environment and selection method. We conclude that environment on scales of $\sim 5h^{-1}\,\mathrm{Mpc}$ regulates X-ray AGN triggering efficiency.
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, California Institute of Technology, Ministerio de Ciencia, Innovación y Universidades, Tata Institute of Fundamental Research, Department of Atomic Energy, Government of India, Eberhard Karls Universität Tübingen, Chinese Academy of Sciences, Max-Planck-Gesellschaft, Ministry of Education, India, Universität Hamburg, Rheinische Friedrich-Wilhelms-Universität Bonn, Leibniz-Institut für Astrophysik Potsdam, Office of Science, Jet Propulsion Laboratory, University of California, Los Angeles, Science and Technology Facilities Council, Leibniz-Gemeinschaft, Russian Academy of Sciences, Agencia Estatal de Investigación, Division of Astronomical Sciences, High Energy Physics, Lawrence Berkeley National Laboratory
Awards: G1044631029, G1079818582, G1105844351, G1143651532, G1175115578, G1286236842, G1632040200, G1813527838, G1863003419, G2262748287, G294895050, G300979063, G3083819904, G3452655474, G3480869486, G3752552830, G4099714421, G419881185, G425668148, G42916606, G4501827968, G491712853, G498139845, G5080475149, G5635532810, G593054264, G6652958823, G6876926712, G7084143925, Management and Operations of the National Optical Astronomy Observatory, G7354628648, G7395345766, G759921648, G7805626310, G7863371703, G8345352404, G8497050386, G8667377315, G969889393
OpenAlex ID: W7213438623