First Fermi-LAT Solar Flare Catalog

Ajello M, Baldini L, Bastieri D, Bellazzini R, Berretta A, Bissaldi E, Blandford RD, Bonino R, Bruel P, Buson S, Cameron RA, Caputo R, Cavazzuti E, Cheung CC, Chiaro G, Costantin D, Cutini S, D'Ammando F, De Palma F, Desiante R, Di Lalla N, Di Venere L, Dirirsa FF, Fegan SJ, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Giordano F, Giroletti M, Green D, Guiriec S, Hays E, Hewitt JW, Horan D, Johannesson G, Kovac'Evic' M, Kuss M, Larsson S, Latronico L, Li J, Longo F, Lovellette MN, Lubrano P, Maldera S, Manfreda A, Marti-Devesa G, Mazziotta MN, Mereu I, Michelson PF, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Negro M, Omodei N, Orienti M, Orlando E, Paneque D, Pei Z, Persic M, Pesce-Rollins M, Petrosian V, Piron F, Porter TA, Principe G, Racusin JL, Raino S, Rando R, Rani B, Razzano M, Razzaque S, Reimer A, Reimer O, Serini D, Sgro C, Siskind EJ, Spandre G, Spinelli P, Tak D, Troja E, Valverde J, Wood K, Zaharijas G (2021)

Publication Type: Journal article

Publication year: 2021


Book Volume: 252

Journal Issue: 2

DOI: 10.3847/1538-4365/abd32e


We present the first Fermi-Large Area Telescope (LAT) solar flare catalog covering the 24th solar cycle. This catalog contains 45 Fermi-LAT solar flares (FLSFs) with emission in the gamma-ray energy band (30 MeV-10 GeV) detected with a significance of >= 5 sigma over the years 2010-2018. A subsample containing 37 of these flares exhibits delayed emission beyond the prompt-impulsive hard X-ray phase, with 21 flares showing delayed emission lasting more than two hours. No prompt-impulsive emission is detected in four of these flares. We also present in this catalog observations of GeV emission from three flares originating from active regions located behind the limb of the visible solar disk. We report the lightcurves, spectra, best proton index, and localization (when possible) for all FLSFs. The gamma-ray spectra are consistent with the decay of pions produced by >300 MeV protons. This work contains the largest sample of high-energy gamma-ray flares ever reported and provides a unique opportunity to perform population studies on the different phases of the flare and thus allowing a new window in solar physics to be opened.

Authors with CRIS profile

Involved external institutions

Clemson University US United States (USA) (US) University of Pisa / Università di Pisa (UniPi) IT Italy (IT) National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN) IT Italy (IT) Università degli Studi di Perugia IT Italy (IT) Politecnico di Bari IT Italy (IT) Stanford University US United States (USA) (US) École Polytechnique - Université Paris-Saclay FR France (FR) Julius-Maximilians-Universität Würzburg DE Germany (DE) National Aeronautics and Space Administration (NASA) US United States (USA) (US) Italian Space Agency / Agenzia Spaziale Italiana (ASI) IT Italy (IT) U.S. Naval Research Laboratory US United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) IT Italy (IT) University of Padua / Universita degli Studi di Padova IT Italy (IT) University of Johannesburg ZA South Africa (ZA) Hiroshima University JP Japan (JP) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics DE Germany (DE) University of North Florida (UNF) US United States (USA) (US) University of Iceland (UI) / Háskóli Íslands IS Iceland (IS) Royal Institute of Technology / Kungliga Tekniska Högskolan (KTH) SE Sweden (SE) Deutsches Elektronen-Synchrotron DESY DE Germany (DE) Leopold-Franzens-Universität Innsbruck / University of Innsbruck AT Austria (AT) Center for Research and Exploration in Space Science & Technology (CRESST) US United States (USA) (US) NYCB Real-Time Computing, Inc. US United States (USA) (US) University of Montpellier / Université Montpellier FR France (FR) Praxis, Inc. US United States (USA) (US)

How to cite


Ajello, M., Baldini, L., Bastieri, D., Bellazzini, R., Berretta, A., Bissaldi, E.,... Zaharijas, G. (2021). First Fermi-LAT Solar Flare Catalog. Astrophysical Journal Supplement Series, 252(2).


Ajello, M., et al. "First Fermi-LAT Solar Flare Catalog." Astrophysical Journal Supplement Series 252.2 (2021).

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