Fermi detection of gamma-ray emission from the hot coronae of radio-quiet active galactic nuclei

Liu JR, Wang JM, Zhao ZH, Torres DF, Thayer JB, Tajima H, Suson DJ, Spinelli P, Spandre G, Siskind EJ, Sgrò C, Serini D, Saz Parkinson PM, Sánchez-Conde M, Reimer O, Reimer A, Razzano M, Rani B, Rando R, Rainò S, Principe G, Porter TA, Pillera R, Pesce-Rollins M, Persic M, Panzarini G, Paneque D, Ormes JF, Orlando E, Orienti M, Omodei N, Niwa R, Negro M, Moskalenko IV, Morselli A, Morishita T, Monzani ME, Mizuno T, Mitthumsiri W, Mirabal N, Michelson PF, Mereu I, Mazziotta MN, Martí-Devesa G, Marcotulli L, Maldera S, Lubrano P, Lorusso L, Loparco F, Longo F, Liodakis I, Li J, Lemoine-Goumard M, Laviron A, Kuss M, Kayanoki T, Karwin C, Hou X, Horan D, Hewitt JW, Hays E, Hashizume M, Guiriec S, Grenier IA, Green D, Giroletti M, Giordano F, Giliberti M, Giglietto N, Germani S, Gasparrini D, Gasbarra C, Gargano F, Fusco P, Funk S, Fukazawa Y, Franckowiak A, Fiori A, Fegan SJ, Domínguez A, Di Venere L, Dinesh A, Di Lalla N, D’Ammando F, Cutini S, Orestano PC, Ciprini S, Cibrario N, Chiaro G, Cavazzuti E, Caraveo PA, Cameron RA, Buson S, Bruel P, Bonino R, Blandford RD, Bissaldi E, Berenji B, Bellazzini R, Gonzalez JB, Bastieri D, Bartolini C, Baldini L, Batista RA, Ajello M, Abdollahi S (2025)

Publication Type: Journal article

Publication year: 2025

Journal

DOI: 10.1038/s41550-025-02538-2

Abstract

Relativistic jets around supermassive black holes are well-known powerful γ-ray emitters. In the absence of the jets in radio-quiet active galactic nuclei, how the supermassive black holes work in γ-ray bands is still unknown despite great observational efforts in the past three decades. Here, considering the previous efforts, we carefully select an active galactic nucleus sample composed of 37 nearby Seyfert galaxies with ultrahard X-rays for γ-ray detection by excluding all potential contamination in this band. Adopting a stacking technique, we report the significant γ-ray detection (test statistic 30.6, or 5.2σ) from the sample using 15-year Fermi-LAT observations. We find the average γ-ray luminosity of the sample to be (1.5 ± 1.0) × 10⁴⁰ erg s⁻¹ at energies of 1–300 GeV. Limited by the well-known pair production from the interaction of γ-rays with low-energy photons, γ-rays of more than several giga-electronvolts are found to originate from an extended corona (~2.7 × 10⁶ gravitational radii), whereas the canonical much more compact X-ray corona (~10 gravitational radii) is responsible for γ-rays of one to several giga-electronvolts. The finding of the compact region lends strong support to the long-time theoretical expectations, but the extended corona is an unexpected finding. One promising scenario is that the electron–positron pairs produced in the compact X-ray corona would expand as a fireball, similar to that in γ-ray bursts, forming the structure of extended corona.

Authors with CRIS profile

Involved external institutions

National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) Università degli Studi di Trieste Italy (IT) National Aeronautics and Space Administration (NASA) United States (USA) (US) Institute of High Energy Physics (IHEP) / 中国科学院高能物理研究所 China (CN) University of Science and Technology of China (USTC) China (CN) Université de Bordeaux France (FR) Institute of Space Sciences (IEEC-CSIC) Spain (ES) Laboratoire Leprince-Ringuet (LLR) France (FR) Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) United States (USA) (US) Nagoya University / 名古屋大学 Japan (JP) Purdue University Northwest / Purdue University Calumet United States (USA) (US) Hiroshima University / 広島大学 Japan (JP) NYCB Real-Time Computing, Inc. United States (USA) (US) Yunnan Observatories China (CN) University of Denver United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) Louisiana State University United States (USA) (US) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) Julius-Maximilians-Universität Würzburg Germany (DE) Santa Cruz Institute for Particle Physics United States (USA) (US) Universidad Autónoma de Madrid (UAM) Spain (ES) Leopold-Franzens-Universität Innsbruck / University of Innsbruck Austria (AT) University of North Florida (UNF) United States (USA) (US) Université Paris-Saclay France (FR) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics Germany (DE) Università degli Studi di Perugia Italy (IT) Clemson University United States (USA) (US) California State University, Los Angeles United States (USA) (US) Universidad de La Laguna Spain (ES) George Washington University (GWU) United States (USA) (US) Ruhr-Universität Bochum (RUB) Germany (DE) Universidad Complutense de Madrid (UCM) Spain (ES) Institut de Recherche en Astrophysique et Planétologie (IRAP) France (FR)

How to cite

APA:

Liu, J.R., Wang, J.M., Zhao, Z.H., Torres, D.F., Thayer, J.B., Tajima, H.,... Abdollahi, S. (2025). Fermi detection of gamma-ray emission from the hot coronae of radio-quiet active galactic nuclei. Nature Astronomy. https://doi.org/10.1038/s41550-025-02538-2

MLA:

Liu, Jun Rong, et al. "Fermi detection of gamma-ray emission from the hot coronae of radio-quiet active galactic nuclei." Nature Astronomy (2025).

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