Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources
Creators: name: LAT Collaboration
name: Abdollahi, S.
name: Acero, F.
name: Ackermann, M.
name: Baldini, L.
name: Ballet, J.
name: Barbiellini, G.
name: Bastieri, D.
name: Bellazzini, R.
name: Berenji, B.
name: Berretta, A.
name: Bissaldi, E.
name: Blandford, R. D.
name: Bonino, R.
name: Bruel, P.
name: Buson, S.
name: Cameron, R. A.
name: Caputo, R.
name: Caraveo, P. A.
name: Castro, D.
name: Chiaro, G.
name: Cibrario, N.
name: Ciprini, S.
name: Coronado-Blázquez, J.
name: Crnogorcevic, M.
name: Cutini, S.
name: D'Ammando, F.
name: De Gaetano, S.
name: Di Lalla, N.
name: Dirirsa, F.
name: Di Venere, L.
name: Domínguez, A.
name: Fegan, S. J.
name: Fiori, A.
name: Fleischhack, H.
name: Franckowiak, A.
name: Fukazawa, Y.
name: Fusco, P.
name: Gammaldi, V.
name: Gargano, F.
name: Gasparrini, D.
name: Giacchino, F.
name: Giglietto, N.
name: Giordano, F.
name: Giroletti, M.
name: Glanzman, T.
name: Green, D.
name: Grenier, I. A.
name: Grondin, M. -H.
name: Guiriec, S.
name: Gustafsson, M.
name: Harding, A. K.
name: Hays, E.
name: Hewitt, J. W.
name: Horan, D.
name: Hou, X.
name: Jóhannesson, G.
name: Kayanoki, T.
name: Kerr, M.
name: Kuss, M.
name: Larsson, S.
name: Latronico, L.
name: Lemoine-Goumard, M.
name: Li, J.
name: Longo, F.
name: Loparco, F.
name: Lubrano, P.
name: Maldera, S.
name: Malyshev, D.
name: Manfreda, A.
name: Martí-Devesa, G.
name: Mazziotta, M. N.
name: Mereu, I.
name: Michelson, P. F.
name: Mirabal, N.
name: Mitthumsiri, W.
name: Mizuno, T.
name: Monzani, M. E.
name: Morselli, A.
name: Moskalenko, I. V.
name: Nuss, E.
name: Omodei, N.
name: Orienti, M.
name: Orlando, E.
name: Ormes, J. F.
name: Paneque, D.
name: Pei, Z.
name: Persic, M.
name: Pesce-Rollins, M.
name: Pillera, R.
name: Poon, H.
name: Porter, T. A.
name: Principe, G.
name: Rainò, S.
name: Rando, R.
name: Rani, B.
name: Razzano, M.
name: Razzaque, S.
name: Reimer, A.
name: Reimer, O.
name: Reposeur, T.
name: Sánchez-Conde, M.
name: Parkinson, P. M. Saz
name: Scotton, L.
name: Serini, D.
name: Sgrò, C.
name: Siskind, E. J.
name: Spandre, G.
name: Spinelli, P.
name: Sueoka, K.
name: Suson, D. J.
name: Tajima, H.
name: Tak, D.
name: Thayer, J. B.
name: Torres, D. F.
name: Troja, E.
name: Valverde, J.
name: Wadiasingh, Z.
name: Wood, K.
name: Zaharijas, G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 years 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.
description: Accepted for publication in The Astrophysical Journal