Fermi-LAT study of Gamma-ray emission in the direction of supernova remnant W49B

A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida, P. Bruel, R. Buehler, S. Buson, G. A. CaliandroR. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, C. D. Dermer, F. De Palma, S. W. Digel, E. Do couto E Silva, P. S. Drell, D. Dumora, C. Favuzzi, S. Funk, P. Fusco, F. Gargano, N. Gehrels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, D. Horan, R. E. Hughes, M. S. Jackson, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, Jun Kataoka, J. Katsuta, J. Knödlseder, M. Kuss, J. Lande, L. Latronico, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, J. Ripken, M. Roth, H. F W Sadrozinski, A. Sander, P. M. Saz Parkinson, C. Sgrò, E. J. Siskind, D. A. Smith, P. D. Smith, P. Spinelli, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, J. Vandenbroucke, V. Vasileiou, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, T. Ylinen, M. Ziegler

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    Abstract

    We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38s is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5 × 1036 (D/8 kpc)2 erg s -1 in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the supernova remnant (SNR) shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral π mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, Ue,p > 104 eVcm-3, for either gamma-ray production mechanism.

    Original languageEnglish
    Pages (from-to)1303-1311
    Number of pages9
    JournalAstrophysical Journal
    Volume722
    Issue number2
    DOIs
    Publication statusPublished - 2010 Oct 20

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    Keywords

    • Acceleration of particles
    • ISM: individual objects (W49B)
    • Radiation mechanisms: non-thermal

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Bloom, E. D., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Buehler, R., Buson, S., ... Ziegler, M. (2010). Fermi-LAT study of Gamma-ray emission in the direction of supernova remnant W49B. Astrophysical Journal, 722(2), 1303-1311. https://doi.org/10.1088/0004-637X/722/2/1303