GRB 221009A: The B.O.A.T. Burst that Shines in Gamma Rays

Axelsson M, Ajello M, Arimoto M, Baldini L, Ballet J, Baring MG, Bartolini C, Bastieri D, Becerra Gonzalez J, Bellazzini R, Berenji B, Bissaldi E, Blandford RD, Bonino R, Bruel P, Buson S, Cameron RA, Caputo R, Caraveo PA, Cavazzuti E, Cheung CC, Chiaro G, Cibrario N, Ciprini S, Cozzolongo G, Cristarella Orestano P, Crnogorcevic M, Cuoco A, Cutini S, D’Ammando F, De Gaetano S, Di Lalla N, Dinesh A, Di Tria R, Di Venere L, Domínguez A, Fegan SJ, Ferrara EC, Fiori A, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Galanti G, Gargano F, Gasbarra C, Germani S, Giacchino F, Giglietto N, Giliberti M, Gill R, Giordano F, Giroletti M, Granot J, Green D, Grenier IA, Guiriec S, Gustafsson M, Hashizume M, Hays E, Hewitt JW, Horan D, Kayanoki T, Kuss M, Laviron A, Li J, Liodakis I, Longo F, Loparco F, Lorusso L, Lott B, Lovellette MN, Lubrano P, Maldera S, Malyshev D, Manfreda A, Martí-Devesa G, Martinelli R, Martinez Castellanos I, Mazziotta MN, McEnery JE, Mereu I, Meyer M, Michelson PF, Mirabal N, Mitthumsiri W, Mizuno T, Monti-Guarnieri P, Monzani ME, Morishita T, Morselli A, Moskalenko IV, Negro M, Niwa R, Omodei N, Orienti M, Orlando E, Paneque D, Panzarini G, Persic M, Pesce-Rollins M, Petrosian V, Pillera R, Piron F, Porter TA, Principe G, Racusin JL, Rainò S, Rando R, Rani B, Razzano M, Razzaque S, Reimer A, Reimer O, Ryde F, Sánchez-Conde M, Saz Parkinson PM, Serini D, Sgrò C, Sharma V, Siskind EJ, Spandre G, Spinelli P, Suson DJ, Tajima H, Tak D, Thayer JB, Torres DF, Valverde J, Zaharijas G, Lesage S, Briggs MS, Burns E, Bala S, Bhat PN, Cleveland WH, Dalessi S, de Barra C, Gibby M, Giles MM, Hamburg R, Hristov BA, Kocevski D, Hui CM, Mailyan B, Malacaria C, McBreen S, Poolakkil S, Roberts OJ, Scotton L, Veres P, von Kienlin A, Wilson-Hodge CA, Wood J (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Book Volume: 277

Article Number: 24

Journal Issue: 1

DOI: 10.3847/1538-4365/ada272

Abstract

We present a complete analysis of Fermi Large Area Telescope (LAT) data of GRB 221009A, the brightest gamma-ray burst (GRB) ever detected. The burst emission above 30 MeV detected by the LAT preceded, by 1 s, the low-energy (<10 MeV) pulse that triggered the Fermi Gamma-Ray Burst Monitor (GBM), as has been observed in other GRBs. The prompt phase of GRB 221009A lasted a few hundred seconds. It was so bright that we identify a bad time interval of 64 s caused by the extremely high flux of hard X-rays and soft gamma rays, during which the event reconstruction efficiency was poor and the dead time fraction quite high. The late-time emission decayed as a power law, but the extrapolation of the late-time emission during the first 450 s suggests that the afterglow started during the prompt emission. We also found that high-energy events observed by the LAT are incompatible with synchrotron origin, and, during the prompt emission, are more likely related to an extra component identified as synchrotron self-Compton (SSC). A remarkable 400 GeV photon, detected by the LAT 33 ks after the GBM trigger and directionally consistent with the location of GRB 221009A, is hard to explain as a product of SSC or TeV electromagnetic cascades, and the process responsible for its origin is uncertain. Because of its proximity and energetic nature, GRB 221009A is an extremely rare event.

Authors with CRIS profile

Involved external institutions

University of Pisa / Università di Pisa (UniPi) Italy (IT) Université Paris-Saclay France (FR) Rice University United States (USA) (US) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) Italy (IT) Universidad de La Laguna Spain (ES) California State University, Los Angeles United States (USA) (US) Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) United States (USA) (US) National Aeronautics and Space Administration (NASA) United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) Italy (IT) Italian Space Agency / Agenzia Spaziale Italiana (ASI) Italy (IT) U.S. Naval Research Laboratory United States (USA) (US) Università degli Studi di Perugia Italy (IT) Royal Institute of Technology / Kungliga Tekniska Högskolan (KTH) Sweden (SE) Clemson University United States (USA) (US) Kanazawa University / 金沢大学 Japan (JP) Laboratoire Leprince-Ringuet (LLR) France (FR) Julius-Maximilians-Universität Würzburg Germany (DE) Universidad Complutense de Madrid (UCM) Spain (ES) Politecnico di Bari Italy (IT) Ruhr-Universität Bochum (RUB) Germany (DE) Hiroshima University / 広島大学 Japan (JP) University of Science and Technology of China (USTC) China (CN) Università degli Studi di Trieste Italy (IT) Université de Bordeaux France (FR) The Aerospace Corporation United States (USA) (US) University of Montpellier / Université Montpellier France (FR) Columbian College of Arts and Sciences United States (USA) (US) Leopold-Franzens-Universität Innsbruck / University of Innsbruck Austria (AT) Universidad Autónoma de Madrid (UAM) Spain (ES) Santa Cruz Institute for Particle Physics United States (USA) (US) NYCB Real-Time Computing, Inc. United States (USA) (US) Purdue University Northwest / Purdue University Calumet United States (USA) (US) Seoul National University (SNU) / 서울대학교 Korea, Republic of (KR) Institute of Space Sciences (IEEC-CSIC) Spain (ES) International Space Science Institute (ISSI) Switzerland (CH) Science and Technology Institute United States (USA) (US) Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics Germany (DE) National Autonomous University of Mexico / Universidad Nacional Autónoma de México (UNAM) Mexico (MX) Open University of Israel / האוניברסיטה הפתוחה Israel (IL) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics Germany (DE) Georg-August-Universität Göttingen Germany (DE) University of North Florida (UNF) United States (USA) (US) University of Southern Denmark / Syddansk Universitet Denmark (DK) Mahidol University / มหาวิทยาลัยมหิดล Thailand (TH) Louisiana State University United States (USA) (US) Nagoya University / 名古屋大学 Japan (JP) University of Nova Gorica / Univerza v Novi Gorici Slovenia (SI) University College Dublin (UCD) Ireland (IE) Jacobs Space Exploration Group United States (USA) (US) The University of Melbourne Australia (AU)

How to cite

APA:

Axelsson, M., Ajello, M., Arimoto, M., Baldini, L., Ballet, J., Baring, M.G.,... Wood, J. (2025). GRB 221009A: The B.O.A.T. Burst that Shines in Gamma Rays. Astrophysical Journal Supplement Series, 277(1). https://doi.org/10.3847/1538-4365/ada272

MLA:

Axelsson, M., et al. "GRB 221009A: The B.O.A.T. Burst that Shines in Gamma Rays." Astrophysical Journal Supplement Series 277.1 (2025).

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