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

Abdo, Aa; Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Bloom, Ed; Bonamente, E; Borgland, Aw; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Casandjian, Jm; Cecchi, C; Celik, O; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Dermer, Cd; de Palma, F; Digel, Sw; Ede, Silva; Drell, Ps; Dumora, D; Favuzzi, Cecilia; Funk, S; Fusco, P; Gargano, F; Gehrels, N; Giglietto, Nicola; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, Ia; Grondin, Mh; Grove, Je; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, Ak; Hayashida, M; Hays, E; Horan, D; Hughes, Re; Jackson, Ms; Johannesson, G; Johnson, As; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Katsuta, J; Knodlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, Sh; Lemoine Goumard, M; Longo, F; Loparco, F; Lovellette, Mn; Lubrano, P; Makeev, A; Mazziotta, Mn; Mizuno, T; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Naumann Godo, M; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ripken, J; Roth, M; Sadrozinski, Hf; Sander, A; Pms, Parkinson; Sgro, C; Siskind, Ej; Smith, Da; Smith, Pd; Spinelli, P; Strickman, Ms; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Tibaldo, L; Tibolla, O; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vitale, V; Waite, Ap; Wang, P; Winer, Bl; Wood, Ks; Ylinen, T; Ziegler, M.

doi:10.1088/0004-637X/722/2/1303

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 38 sigma 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 x 10(36) (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 pi 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, U(e,p) > 10(4) eV cm(-3), for either gamma-ray production mechanism.

Fermi-LAT study of Gamma-ray emission in the direction of supernova remnant W49B / Abdo, Aa; Ackermann, M; Ajello, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Bloom, Ed; Bonamente, E; Borgland, Aw; Bouvier, A; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Casandjian, Jm; Cecchi, C; Celik, O; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Dermer, Cd; de Palma, F; Digel, Sw; Silva, Ede; Drell, Ps; Dumora, D; Favuzzi, Cecilia; Funk, S; Fusco, P; Gargano, F; Gehrels, N; Giglietto, Nicola; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, Ia; Grondin, Mh; Grove, Je; Guillemot, L; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, Ak; Hayashida, M; Hays, E; Horan, D; Hughes, Re; Jackson, Ms; Johannesson, G; Johnson, As; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Katsuta, J; Knodlseder, J; Kuss, M; Lande, J; Latronico, L; Lee, Sh; Lemoine Goumard, M; Longo, F; Loparco, F; Lovellette, Mn; Lubrano, P; Makeev, A; Mazziotta, Mn; Mizuno, T; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Naumann Godo, M; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ripken, J; Roth, M; Sadrozinski, Hf; Sander, A; Parkinson, Pms; Sgro, C; Siskind, Ej; Smith, Da; Smith, Pd; Spinelli, P; Strickman, Ms; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Tibaldo, L; Tibolla, O; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vitale, V; Waite, Ap; Wang, P; Winer, Bl; Wood, Ks; Ylinen, T; Ziegler, M.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - ELETTRONICO. - 722:2(2010), pp. 1303-1311. [10.1088/0004-637X/722/2/1303]