Detection of the characteristic pion-decay signature in supernova remnants

M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. BuehlerG. Busetto, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, E. Charles, S. Chaty, R. C G Chaves, A. Chekhtman, C. C. Cheung, J. Chiang, G. Chiaro, A. N. Cillis, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Corbel, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, E. C. 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, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, K. Hayashi, E. Hays, J. W. Hewitt, A. B. Hill, R. E. Hughes, M. S. Jackson, T. Jogler, G. Jóhannesson, A. S. Johnson, T. Kamae, Jun Kataoka, J. Katsuta, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, G. M. Madejski, F. Massaro, M. Mayer, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, R. P. Mignani, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, R. Nemmen, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J. F. Ormes, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, S. Ritz, C. Romoli, M. Sánchez-Conde, A. Schulz, C. Sgrò, P. E. Simeon, E. J. Siskind, D. A. Smith, G. Spandre, P. Spinelli, F. W. Stecker, A. W. Strong, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, D. J. Thompson, S. E. Thorsett, L. Tibaldo, O. Tibolla, M. Tinivella, E. Troja, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, M. Werner, B. L. Winer, K. S. Wood, M. Wood, R. Yamazaki, Z. Yang, S. Zimmer

    Research output: Contribution to journalArticle

    438 Citations (Scopus)

    Abstract

    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.

    Original languageEnglish
    Pages (from-to)807-811
    Number of pages5
    JournalScience
    Volume339
    Issue number6121
    DOIs
    Publication statusPublished - 2013 Feb 15

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    Mesons
    Gamma Rays
    Protons
    Telescopes
    Electrons

    ASJC Scopus subject areas

    • General

    Cite this

    Ackermann, M., Ajello, M., Allafort, A., Baldini, L., Ballet, J., Barbiellini, G., ... Zimmer, S. (2013). Detection of the characteristic pion-decay signature in supernova remnants. Science, 339(6121), 807-811. https://doi.org/10.1126/science.1231160

    Detection of the characteristic pion-decay signature in supernova remnants. / Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö; Charles, E.; Chaty, S.; Chaves, R. C G; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Chiaro, G.; Cillis, A. N.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Corbel, S.; Cutini, S.; D'Ammando, F.; De Angelis, A.; De Palma, F.; Dermer, C. D.; Do Couto E Silva, E.; Drell, P. S.; Drlica-Wagner, A.; Falletti, L.; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Germani, S.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M. H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hayashi, K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Hughes, R. E.; Jackson, M. S.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Kataoka, Jun; Katsuta, J.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Massaro, F.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mignani, R. P.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Ritz, S.; Romoli, C.; Sánchez-Conde, M.; Schulz, A.; Sgrò, C.; Simeon, P. E.; Siskind, E. J.; Smith, D. A.; Spandre, G.; Spinelli, P.; Stecker, F. W.; Strong, A. W.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.; Tibolla, O.; Tinivella, M.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Werner, M.; Winer, B. L.; Wood, K. S.; Wood, M.; Yamazaki, R.; Yang, Z.; Zimmer, S.

    In: Science, Vol. 339, No. 6121, 15.02.2013, p. 807-811.

    Research output: Contribution to journalArticle

    Ackermann, M, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Bechtol, K, Bellazzini, R, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Busetto, G, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Casandjian, JM, Cecchi, C, Çelik, Ö, Charles, E, Chaty, S, Chaves, RCG, Chekhtman, A, Cheung, CC, Chiang, J, Chiaro, G, Cillis, AN, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, Corbel, S, Cutini, S, D'Ammando, F, De Angelis, A, De Palma, F, Dermer, CD, Do Couto E Silva, E, Drell, PS, Drlica-Wagner, A, Falletti, L, Favuzzi, C, Ferrara, EC, Franckowiak, A, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Germani, S, Giglietto, N, Giommi, P, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grondin, MH, Grove, JE, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashida, M, Hayashi, K, Hays, E, Hewitt, JW, Hill, AB, Hughes, RE, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Kamae, T, Kataoka, J, Katsuta, J, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Latronico, L, Lemoine-Goumard, M, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Madejski, GM, Massaro, F, Mayer, M, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, Mignani, RP, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nakamori, T, Nemmen, R, Nuss, E, Ohno, M, Ohsugi, T, Omodei, N, Orienti, M, Orlando, E, Ormes, JF, Paneque, D, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Rainò, S, Rando, R, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Ritz, S, Romoli, C, Sánchez-Conde, M, Schulz, A, Sgrò, C, Simeon, PE, Siskind, EJ, Smith, DA, Spandre, G, Spinelli, P, Stecker, FW, Strong, AW, Suson, DJ, Tajima, H, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JG, Thayer, JB, Thompson, DJ, Thorsett, SE, Tibaldo, L, Tibolla, O, Tinivella, M, Troja, E, Uchiyama, Y, Usher, TL, Vandenbroucke, J, Vasileiou, V, Vianello, G, Vitale, V, Waite, AP, Werner, M, Winer, BL, Wood, KS, Wood, M, Yamazaki, R, Yang, Z & Zimmer, S 2013, 'Detection of the characteristic pion-decay signature in supernova remnants', Science, vol. 339, no. 6121, pp. 807-811. https://doi.org/10.1126/science.1231160
    Ackermann M, Ajello M, Allafort A, Baldini L, Ballet J, Barbiellini G et al. Detection of the characteristic pion-decay signature in supernova remnants. Science. 2013 Feb 15;339(6121):807-811. https://doi.org/10.1126/science.1231160
    Ackermann, M. ; Ajello, M. ; Allafort, A. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Baring, M. G. ; Bastieri, D. ; Bechtol, K. ; Bellazzini, R. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bottacini, E. ; Brandt, T. J. ; Bregeon, J. ; Brigida, M. ; Bruel, P. ; Buehler, R. ; Busetto, G. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Caraveo, P. A. ; Casandjian, J. M. ; Cecchi, C. ; Çelik, Ö ; Charles, E. ; Chaty, S. ; Chaves, R. C G ; Chekhtman, A. ; Cheung, C. C. ; Chiang, J. ; Chiaro, G. ; Cillis, A. N. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Cominsky, L. R. ; Conrad, J. ; Corbel, S. ; Cutini, S. ; D'Ammando, F. ; De Angelis, A. ; De Palma, F. ; Dermer, C. D. ; Do Couto E Silva, E. ; Drell, P. S. ; Drlica-Wagner, A. ; Falletti, L. ; Favuzzi, C. ; Ferrara, E. C. ; Franckowiak, A. ; Fukazawa, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Germani, S. ; Giglietto, N. ; Giommi, P. ; Giordano, F. ; Giroletti, M. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Grondin, M. H. ; Grove, J. E. ; Guiriec, S. ; Hadasch, D. ; Hanabata, Y. ; Harding, A. K. ; Hayashida, M. ; Hayashi, K. ; Hays, E. ; Hewitt, J. W. ; Hill, A. B. ; Hughes, R. E. ; Jackson, M. S. ; Jogler, T. ; Jóhannesson, G. ; Johnson, A. S. ; Kamae, T. ; Kataoka, Jun ; Katsuta, J. ; Knödlseder, J. ; Kuss, M. ; Lande, J. ; Larsson, S. ; Latronico, L. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lovellette, M. N. ; Lubrano, P. ; Madejski, G. M. ; Massaro, F. ; Mayer, M. ; Mazziotta, M. N. ; McEnery, J. E. ; Mehault, J. ; Michelson, P. F. ; Mignani, R. P. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Nakamori, T. ; Nemmen, R. ; Nuss, E. ; Ohno, M. ; Ohsugi, T. ; Omodei, N. ; Orienti, M. ; Orlando, E. ; Ormes, J. F. ; Paneque, D. ; Perkins, J. S. ; Pesce-Rollins, M. ; Piron, F. ; Pivato, G. ; Rainò, S. ; Rando, R. ; Razzano, M. ; Razzaque, S. ; Reimer, A. ; Reimer, O. ; Ritz, S. ; Romoli, C. ; Sánchez-Conde, M. ; Schulz, A. ; Sgrò, C. ; Simeon, P. E. ; Siskind, E. J. ; Smith, D. A. ; Spandre, G. ; Spinelli, P. ; Stecker, F. W. ; Strong, A. W. ; Suson, D. J. ; Tajima, H. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. G. ; Thayer, J. B. ; Thompson, D. J. ; Thorsett, S. E. ; Tibaldo, L. ; Tibolla, O. ; Tinivella, M. ; Troja, E. ; Uchiyama, Y. ; Usher, T. L. ; Vandenbroucke, J. ; Vasileiou, V. ; Vianello, G. ; Vitale, V. ; Waite, A. P. ; Werner, M. ; Winer, B. L. ; Wood, K. S. ; Wood, M. ; Yamazaki, R. ; Yang, Z. ; Zimmer, S. / Detection of the characteristic pion-decay signature in supernova remnants. In: Science. 2013 ; Vol. 339, No. 6121. pp. 807-811.
    @article{0db9147c1ac3482c9856a821e6af70e0,
    title = "Detection of the characteristic pion-decay signature in supernova remnants",
    abstract = "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.",
    author = "M. Ackermann and M. Ajello and A. Allafort and L. Baldini and J. Ballet and G. Barbiellini and Baring, {M. G.} and D. Bastieri and K. Bechtol and R. Bellazzini and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and E. Bottacini and Brandt, {T. J.} and J. Bregeon and M. Brigida and P. Bruel and R. Buehler and G. Busetto and S. Buson and Caliandro, {G. A.} and Cameron, {R. A.} and Caraveo, {P. A.} and Casandjian, {J. M.} and C. Cecchi and {\"O} {\cC}elik and E. Charles and S. Chaty and Chaves, {R. C G} and A. Chekhtman and Cheung, {C. C.} and J. Chiang and G. Chiaro and Cillis, {A. N.} and S. Ciprini and R. Claus and J. Cohen-Tanugi and Cominsky, {L. R.} and J. Conrad and S. Corbel and S. Cutini and F. D'Ammando and {De Angelis}, A. and {De Palma}, F. and Dermer, {C. D.} and {Do Couto E Silva}, E. and Drell, {P. S.} and A. Drlica-Wagner and L. Falletti and C. Favuzzi and Ferrara, {E. C.} and A. Franckowiak and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and S. Germani and N. Giglietto and P. Giommi and F. Giordano and M. Giroletti and T. Glanzman and G. Godfrey and Grenier, {I. A.} and Grondin, {M. H.} and Grove, {J. E.} and S. Guiriec and D. Hadasch and Y. Hanabata and Harding, {A. K.} and M. Hayashida and K. Hayashi and E. Hays and Hewitt, {J. W.} and Hill, {A. B.} and Hughes, {R. E.} and Jackson, {M. S.} and T. Jogler and G. J{\'o}hannesson and Johnson, {A. S.} and T. Kamae and Jun Kataoka and J. Katsuta and J. Kn{\"o}dlseder and M. Kuss and J. Lande and S. Larsson and L. Latronico and M. Lemoine-Goumard and F. Longo and F. Loparco and Lovellette, {M. N.} and P. Lubrano and Madejski, {G. M.} and F. Massaro and M. Mayer and Mazziotta, {M. N.} and McEnery, {J. E.} and J. Mehault and Michelson, {P. F.} and Mignani, {R. P.} and W. Mitthumsiri and T. Mizuno and Moiseev, {A. A.} and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and T. Nakamori and R. Nemmen and E. Nuss and M. Ohno and T. Ohsugi and N. Omodei and M. Orienti and E. Orlando and Ormes, {J. F.} and D. Paneque and Perkins, {J. S.} and M. Pesce-Rollins and F. Piron and G. Pivato and S. Rain{\`o} and R. Rando and M. Razzano and S. Razzaque and A. Reimer and O. Reimer and S. Ritz and C. Romoli and M. S{\'a}nchez-Conde and A. Schulz and C. Sgr{\`o} and Simeon, {P. E.} and Siskind, {E. J.} and Smith, {D. A.} and G. Spandre and P. Spinelli and Stecker, {F. W.} and Strong, {A. W.} and Suson, {D. J.} and H. Tajima and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. G.} and Thayer, {J. B.} and Thompson, {D. J.} and Thorsett, {S. E.} and L. Tibaldo and O. Tibolla and M. Tinivella and E. Troja and Y. Uchiyama and Usher, {T. L.} and J. Vandenbroucke and V. Vasileiou and G. Vianello and V. Vitale and Waite, {A. P.} and M. Werner and Winer, {B. L.} and Wood, {K. S.} and M. Wood and R. Yamazaki and Z. Yang and S. Zimmer",
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    publisher = "American Association for the Advancement of Science",
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    TY - JOUR

    T1 - Detection of the characteristic pion-decay signature in supernova remnants

    AU - Ackermann, M.

    AU - Ajello, M.

    AU - Allafort, A.

    AU - Baldini, L.

    AU - Ballet, J.

    AU - Barbiellini, G.

    AU - Baring, M. G.

    AU - Bastieri, D.

    AU - Bechtol, K.

    AU - Bellazzini, R.

    AU - Blandford, R. D.

    AU - Bloom, E. D.

    AU - Bonamente, E.

    AU - Borgland, A. W.

    AU - Bottacini, E.

    AU - Brandt, T. J.

    AU - Bregeon, J.

    AU - Brigida, M.

    AU - Bruel, P.

    AU - Buehler, R.

    AU - Busetto, G.

    AU - Buson, S.

    AU - Caliandro, G. A.

    AU - Cameron, R. A.

    AU - Caraveo, P. A.

    AU - Casandjian, J. M.

    AU - Cecchi, C.

    AU - Çelik, Ö

    AU - Charles, E.

    AU - Chaty, S.

    AU - Chaves, R. C G

    AU - Chekhtman, A.

    AU - Cheung, C. C.

    AU - Chiang, J.

    AU - Chiaro, G.

    AU - Cillis, A. N.

    AU - Ciprini, S.

    AU - Claus, R.

    AU - Cohen-Tanugi, J.

    AU - Cominsky, L. R.

    AU - Conrad, J.

    AU - Corbel, S.

    AU - Cutini, S.

    AU - D'Ammando, F.

    AU - De Angelis, A.

    AU - De Palma, F.

    AU - Dermer, C. D.

    AU - Do Couto E Silva, E.

    AU - Drell, P. S.

    AU - Drlica-Wagner, A.

    AU - Falletti, L.

    AU - Favuzzi, C.

    AU - Ferrara, E. C.

    AU - Franckowiak, A.

    AU - Fukazawa, Y.

    AU - Funk, S.

    AU - Fusco, P.

    AU - Gargano, F.

    AU - Germani, S.

    AU - Giglietto, N.

    AU - Giommi, P.

    AU - Giordano, F.

    AU - Giroletti, M.

    AU - Glanzman, T.

    AU - Godfrey, G.

    AU - Grenier, I. A.

    AU - Grondin, M. H.

    AU - Grove, J. E.

    AU - Guiriec, S.

    AU - Hadasch, D.

    AU - Hanabata, Y.

    AU - Harding, A. K.

    AU - Hayashida, M.

    AU - Hayashi, K.

    AU - Hays, E.

    AU - Hewitt, J. W.

    AU - Hill, A. B.

    AU - Hughes, R. E.

    AU - Jackson, M. S.

    AU - Jogler, T.

    AU - Jóhannesson, G.

    AU - Johnson, A. S.

    AU - Kamae, T.

    AU - Kataoka, Jun

    AU - Katsuta, J.

    AU - Knödlseder, J.

    AU - Kuss, M.

    AU - Lande, J.

    AU - Larsson, S.

    AU - Latronico, L.

    AU - Lemoine-Goumard, M.

    AU - Longo, F.

    AU - Loparco, F.

    AU - Lovellette, M. N.

    AU - Lubrano, P.

    AU - Madejski, G. M.

    AU - Massaro, F.

    AU - Mayer, M.

    AU - Mazziotta, M. N.

    AU - McEnery, J. E.

    AU - Mehault, J.

    AU - Michelson, P. F.

    AU - Mignani, R. P.

    AU - Mitthumsiri, W.

    AU - Mizuno, T.

    AU - Moiseev, A. A.

    AU - Monzani, M. E.

    AU - Morselli, A.

    AU - Moskalenko, I. V.

    AU - Murgia, S.

    AU - Nakamori, T.

    AU - Nemmen, R.

    AU - Nuss, E.

    AU - Ohno, M.

    AU - Ohsugi, T.

    AU - Omodei, N.

    AU - Orienti, M.

    AU - Orlando, E.

    AU - Ormes, J. F.

    AU - Paneque, D.

    AU - Perkins, J. S.

    AU - Pesce-Rollins, M.

    AU - Piron, F.

    AU - Pivato, G.

    AU - Rainò, S.

    AU - Rando, R.

    AU - Razzano, M.

    AU - Razzaque, S.

    AU - Reimer, A.

    AU - Reimer, O.

    AU - Ritz, S.

    AU - Romoli, C.

    AU - Sánchez-Conde, M.

    AU - Schulz, A.

    AU - Sgrò, C.

    AU - Simeon, P. E.

    AU - Siskind, E. J.

    AU - Smith, D. A.

    AU - Spandre, G.

    AU - Spinelli, P.

    AU - Stecker, F. W.

    AU - Strong, A. W.

    AU - Suson, D. J.

    AU - Tajima, H.

    AU - Takahashi, H.

    AU - Takahashi, T.

    AU - Tanaka, T.

    AU - Thayer, J. G.

    AU - Thayer, J. B.

    AU - Thompson, D. J.

    AU - Thorsett, S. E.

    AU - Tibaldo, L.

    AU - Tibolla, O.

    AU - Tinivella, M.

    AU - Troja, E.

    AU - Uchiyama, Y.

    AU - Usher, T. L.

    AU - Vandenbroucke, J.

    AU - Vasileiou, V.

    AU - Vianello, G.

    AU - Vitale, V.

    AU - Waite, A. P.

    AU - Werner, M.

    AU - Winer, B. L.

    AU - Wood, K. S.

    AU - Wood, M.

    AU - Yamazaki, R.

    AU - Yang, Z.

    AU - Zimmer, S.

    PY - 2013/2/15

    Y1 - 2013/2/15

    N2 - 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.

    AB - 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.

    UR - http://www.scopus.com/inward/record.url?scp=84873619168&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84873619168&partnerID=8YFLogxK

    U2 - 10.1126/science.1231160

    DO - 10.1126/science.1231160

    M3 - Article

    C2 - 23413352

    AN - SCOPUS:84873619168

    VL - 339

    SP - 807

    EP - 811

    JO - Science

    JF - Science

    SN - 0036-8075

    IS - 6121

    ER -