Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources

Abdollahi S, Acero F, Ackermann M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bellazzini R, Berenji B, Berretta A, Bissaldi E, Blandford RD, Bonino R, Bruel P, Buson S, Cameron RA, Caputo R, Caraveo PA, Castro D, Chiaro G, Cibrario N, Ciprini S, Coronado-Blazquez J, Crnogorcevic M, Cutini S, D'Ammando F, De Gaetano S, Di Lalla N, Dirirsa F, Di Venere L, Dominguez A, Fegan SJ, Fiori A, Fleischhack H, Franckowiak A, Fukazawa Y, Fusco P, Gammaldi , Gargano F, Gasparrini D, Giacchino F, Giglietto N, Giordano F, Giroletti M, Glanzman T, Green D, Grenier IA, Grondin MH, Guiriec S, Gustafsson M, Harding AK, Hays E, Hewitt JW, Horan D, Hou X, Johannesson G, Kayanoki T, Kerr M, Kuss M, Larsson S, Latronico L, Lemoine-Goumard M, Li J, Longo F, Loparco F, Lubrano P, Maldera S, Malyshev D, Manfreda A, Martí-Devesa G, Mazziotta MN, Mereu , Michelson PF, Mirabal N, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko I, Nuss E, Omodei N, Orienti M, Orlando E, Ormes JF, Paneque D, Pei Z, Persic M, Pesce-Rollins M, Pillera R, Poon H, Porter TA, Principe G, Raino S, Rando R, Rani B, Razzano M, Razzaque S, Reimer A, Reimer O, Reposeur T, Sanchez-Conde M, Parkinson PMS, Scotton L, Serini D, Sgro C, Siskind EJ, Spandre G, Spinelli P, Sueoka K, Suson DJ, Tajima H, Tak D, Thayer JB, Torres DF, Troja E, Valverde J, Wadiasingh Z, Wood K, Zaharijas G (2022)

Publication Type: Journal article

Publication year: 2022


Book Volume: 933

Journal Issue: 2

DOI: 10.3847/1538-4357/ac704f


Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma-rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four supernova remnants (SNRs), IC 443, W44, W49B, and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5 degrees from the Galactic plane. Using 8 yr of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS I+61 303; the colliding wind binary eta Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites.

Authors with CRIS profile

Involved external institutions

Université Fédérale de Toulouse Midi-Pyrénées FR France (FR) École Polytechnique - Université Paris-Saclay FR France (FR) Deutsches Elektronen-Synchrotron DESY DE Germany (DE) 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) University of Bari Aldo Moro / Università degli Studi di Bari Aldo Moro IT Italy (IT) Stanford University US United States (USA) (US) National Aeronautics and Space Administration (NASA) US United States (USA) (US) University of Maryland US United States (USA) (US) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) IT Italy (IT) Ethiopian Space Science and Technology Institute (ESSTI) / የኢትዮጵያ ስፔስ ሳይንስ እና ቴክኖሎጂ ተቋም ET Ethiopia (ET) University of North Florida (UNF) US United States (USA) (US) Hiroshima University / 広島大学 JP Japan (JP) Purdue University Northwest / Purdue University Calumet US United States (USA) (US) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) ES Spain (ES) Max-Planck-Institut für Physik (Werner-Heisenberg-Institut, MPP) / Max Planck Institute for Physics DE Germany (DE) Institut national de physique nucléaire et de physique des particules (IN2P3) FR France (FR) Georg-August-Universität Göttingen DE Germany (DE) Los Alamos National Laboratory US United States (USA) (US) Chinese Academy of Sciences (CAS) / 中国科学院 CN China (CN) Leopold-Franzens-Universität Innsbruck / University of Innsbruck AT Austria (AT) Universidad Autónoma de Madrid (UAM) ES Spain (ES) NYCB Real-Time Computing, Inc. US United States (USA) (US) Praxis, Inc. US United States (USA) (US) California State University, Los Angeles US United States (USA) (US) University of Iceland (UI) / Háskóli Íslands IS Iceland (IS) U.S. Naval Research Laboratory US United States (USA) (US) Royal Institute of Technology / Kungliga Tekniska Högskolan (KTH) SE Sweden (SE) University of Science and Technology of China (USTC) CN China (CN) University of California Santa Cruz US United States (USA) (US) University of Montpellier / Université Montpellier FR France (FR) University of Nova Gorica / Univerza v Novi Gorici SI Slovenia (SI) Julius-Maximilians-Universität Würzburg DE Germany (DE) Universidad Complutense de Madrid (UCM) ES Spain (ES) Ruhr-Universität Bochum (RUB) DE Germany (DE) Mahidol University / มหาวิทยาลัยมหิดล TH Thailand (TH) University of Denver US United States (USA) (US) University of Padua / Universita degli Studi di Padova IT Italy (IT) University of Johannesburg ZA South Africa (ZA)

How to cite


Abdollahi, S., Acero, F., Ackermann, M., Baldini, L., Ballet, J., Barbiellini, G.,... Zaharijas, G. (2022). Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources. Astrophysical Journal, 933(2).


Abdollahi, S., et al. "Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources." Astrophysical Journal 933.2 (2022).

BibTeX: Download