Authors
Markus Ackermann, Marco Ajello, A Allafort, Luca Baldini, Jean Ballet, Guido Barbiellini, MG Baring, Denis Bastieri, K Bechtol, R Bellazzini, RD Blandford, ED Bloom, Emanuele Bonamente, AW Borgland, E Bottacini, TJ Brandt, J Bregeon, M Brigida, Pascal Bruel, R Buehler, Giovanni Busetto, Sara Buson, GA Caliandro, RA Cameron, PA Caraveo, JM Casandjian, Claudia Cecchi, Ö Çelik, E Charles, S Chaty, RCG Chaves, A Chekhtman, CC Cheung, J Chiang, G Chiaro, AN Cillis, S Ciprini, R Claus, J Cohen-Tanugi, LR Cominsky, Jan Conrad, S Corbel, S Cutini, Filippo D'Ammando, A De Angelis, F De Palma, CD Dermer, E Do Couto e Silva, PS Drell, A Drlica-Wagner, L Falletti, C Favuzzi, EC Ferrara, A Franckowiak, Y Fukazawa, S Funk, P Fusco, F Gargano, S Germani, N Giglietto, P Giommi, F Giordano, M Giroletti, T Glanzman, G Godfrey, IA Grenier, M-H Grondin, JE Grove, S Guiriec, D Hadasch, Y Hanabata, AK Harding, M Hayashida, K Hayashi, E Hays, JW Hewitt, AB Hill, RE Hughes, MS Jackson, T Jogler, G Jóhannesson, AS Johnson, T Kamae, J Kataoka, J Katsuta, Jürgen Knödlseder, M Kuss, J Lande, Stefan Larsson, L Latronico, M Lemoine-Goumard, Francesco Longo, F Loparco, MN Lovellette, P Lubrano, GM Madejski, Francesco Massaro, M Mayer, MN Mazziotta, JE McEnery, J Mehault, PF Michelson, RP Mignani, W Mitthumsiri, T Mizuno, AA Moiseev, ME Monzani, A Morselli, IV Moskalenko, S Murgia, T Nakamori, R Nemmen, E Nuss, M Ohno, T Ohsugi, N Omodei, M Orienti, E Orlando, JF Ormes, D Paneque, JS Perkins, M Pesce-Rollins, F Piron, Giovanna Pivato, S Rainò, Riccardo Rando, Massimiliano Razzano, S Razzaque, A Reimer, O Reimer, S Ritz, C Romoli, M Sánchez-Conde, A Schulz, C Sgrò, PE Simeon, EJ Siskind, DA Smith, G Spandre, P Spinelli, FW Stecker, AW Strong, DJ Suson, H Tajima, H Takahashi, T Takahashi, T Tanaka, JG Thayer, JB Thayer, DJ Thompson
Publication date
2013/2/15
Journal
Science
Volume
339
Issue
6121
Pages
807-811
Publisher
American Association for the Advancement of Science
Description
Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.
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Scholar articles
M Ackermann, M Ajello, A Allafort, L Baldini, J Ballet… - Science, 2013