Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C

A. A. Abdo, M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, M. G. Baring, D. Bastieri, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. Bregeon, A. Brez, M. Brigida & 157 others P. Bruel, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, M. Dormody, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, G. Giavitto, B. Giebels, N. Giglietto, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, M. Hayashida, E. Hays, R. E. Hughes, M. S. Jackson, G. Jóhannesson, A. S. Johnson, T. J. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, Jun Kataoka, J. Katsuta, N. Kawai, M. Kerr, J. Knödlseder, M. L. Kocian, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, A. Makeev, M. N. Mazziotta, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, S. Ritz, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F W Sadrozinski, D. Sanchez, A. Sander, P. M. Saz Parkinson, J. D. Scargle, T. L. Schalk, C. Sgrò, E. J. Siskind, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, V. Vasileiou, C. Venter, N. Vilchez, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, R. Yamazaki, T. Ylinen, M. Ziegler

    Research output: Contribution to journalArticle

    202 Citations (Scopus)

    Abstract

    The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (104 yr) ∼ with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 × 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral π mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to ̄n H Wp ≃ 5× 1051 (D/6kpc)2 erg cm-2. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.

    Original languageEnglish
    JournalAstrophysical Journal
    Volume706
    Issue number1 PART 2
    DOIs
    Publication statusPublished - 2009

    Fingerprint

    supernova remnants
    gamma rays
    telescopes
    radio
    erg
    cosmic ray
    shock
    energy
    Fermi Gamma-ray Space Telescope
    gas density
    molecular clouds
    electron density
    supernovae
    cosmic rays
    synchrotrons
    energy spectra
    x rays
    mesons
    collision
    luminosity

    Keywords

    • Acceleration of particles
    • ISM: individual (W51C)
    • 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., ... Ziegler, M. (2009). Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C. Astrophysical Journal, 706(1 PART 2). https://doi.org/10.1088/0004-637X/706/1/L1

    Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C. / Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Cutini, S.; Dermer, C. D.; De Angelis, A.; De Palma, F.; Digel, S. W.; Dormody, M.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giavitto, G.; Giebels, B.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M. H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.; Hughes, R. E.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, Jun; Katsuta, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kocian, M. L.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Ritz, S.; Rodriguez, A. Y.; Romani, R. W.; Roth, M.; Ryde, F.; Sadrozinski, H. F W; Sanchez, D.; Sander, A.; Saz Parkinson, P. M.; Scargle, J. D.; Schalk, T. L.; Sgrò, C.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Vasileiou, V.; Venter, C.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yamazaki, R.; Ylinen, T.; Ziegler, M.

    In: Astrophysical Journal, Vol. 706, No. 1 PART 2, 2009.

    Research output: Contribution to journalArticle

    Abdo, AA, Ackermann, M, Ajello, M, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Baughman, BM, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bouvier, A, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, TH, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Casandjian, JM, Cecchi, C, Çelik, Ö, Chekhtman, A, Cheung, CC, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, Cutini, S, Dermer, CD, De Angelis, A, De Palma, F, Digel, SW, Dormody, M, Do Couto E Silva, E, Drell, PS, Dubois, R, Dumora, D, Farnier, C, Favuzzi, C, Fegan, SJ, Focke, WB, Fortin, P, Frailis, M, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Germani, S, Giavitto, G, Giebels, B, Giglietto, N, Giordano, F, Glanzman, T, Godfrey, G, Grenier, IA, Grondin, MH, Grove, JE, Guillemot, L, Guiriec, S, Hanabata, Y, Harding, AK, Hayashida, M, Hays, E, Hughes, RE, Jackson, MS, Jóhannesson, G, Johnson, AS, Johnson, TJ, Johnson, WN, Kamae, T, Katagiri, H, Kataoka, J, Katsuta, J, Kawai, N, Kerr, M, Knödlseder, J, Kocian, ML, Kuss, M, Lande, J, Latronico, L, Lemoine-Goumard, M, Longo, F, Loparco, F, Lott, B, Lovellette, MN, Lubrano, P, Makeev, A, Mazziotta, MN, McEnery, JE, Meurer, C, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nakamori, T, Nolan, PL, Norris, JP, Nuss, E, Ohsugi, T, Okumura, A, Omodei, N, Orlando, E, Ormes, JF, Paneque, D, Parent, D, Pelassa, V, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, TA, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reposeur, T, Ritz, S, Rodriguez, AY, Romani, RW, Roth, M, Ryde, F, Sadrozinski, HFW, Sanchez, D, Sander, A, Saz Parkinson, PM, Scargle, JD, Schalk, TL, Sgrò, C, Siskind, EJ, Smith, DA, Smith, PD, Spandre, G, Spinelli, P, Strickman, MS, Suson, DJ, Tajima, H, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JB, Thayer, JG, Thompson, DJ, Tibaldo, L, Tibolla, O, Torres, DF, Tosti, G, Tramacere, A, Uchiyama, Y, Usher, TL, Vasileiou, V, Venter, C, Vilchez, N, Vitale, V, Waite, AP, Wang, P, Winer, BL, Wood, KS, Yamazaki, R, Ylinen, T & Ziegler, M 2009, 'Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C', Astrophysical Journal, vol. 706, no. 1 PART 2. https://doi.org/10.1088/0004-637X/706/1/L1
    Abdo, A. A. ; Ackermann, M. ; Ajello, M. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Baring, M. G. ; Bastieri, D. ; Baughman, B. M. ; Bechtol, K. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bouvier, A. ; Bregeon, J. ; Brez, A. ; Brigida, M. ; Bruel, P. ; Burnett, T. H. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Caraveo, P. A. ; Casandjian, J. M. ; Cecchi, C. ; Çelik, Ö ; Chekhtman, A. ; Cheung, C. C. ; Chiang, J. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Cominsky, L. R. ; Conrad, J. ; Cutini, S. ; Dermer, C. D. ; De Angelis, A. ; De Palma, F. ; Digel, S. W. ; Dormody, M. ; Do Couto E Silva, E. ; Drell, P. S. ; Dubois, R. ; Dumora, D. ; Farnier, C. ; Favuzzi, C. ; Fegan, S. J. ; Focke, W. B. ; Fortin, P. ; Frailis, M. ; Fukazawa, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Gehrels, N. ; Germani, S. ; Giavitto, G. ; Giebels, B. ; Giglietto, N. ; Giordano, F. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Grondin, M. H. ; Grove, J. E. ; Guillemot, L. ; Guiriec, S. ; Hanabata, Y. ; Harding, A. K. ; Hayashida, M. ; Hays, E. ; Hughes, R. E. ; Jackson, M. S. ; Jóhannesson, G. ; Johnson, A. S. ; Johnson, T. J. ; Johnson, W. N. ; Kamae, T. ; Katagiri, H. ; Kataoka, Jun ; Katsuta, J. ; Kawai, N. ; Kerr, M. ; Knödlseder, J. ; Kocian, M. L. ; Kuss, M. ; Lande, J. ; Latronico, L. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lott, B. ; Lovellette, M. N. ; Lubrano, P. ; Makeev, A. ; Mazziotta, M. N. ; McEnery, J. E. ; Meurer, C. ; Michelson, P. F. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Nakamori, T. ; Nolan, P. L. ; Norris, J. P. ; Nuss, E. ; Ohsugi, T. ; Okumura, A. ; Omodei, N. ; Orlando, E. ; Ormes, J. F. ; Paneque, D. ; Parent, D. ; Pelassa, V. ; Pepe, M. ; Pesce-Rollins, M. ; Piron, F. ; Porter, T. A. ; Rainò, S. ; Rando, R. ; Razzano, M. ; Reimer, A. ; Reimer, O. ; Reposeur, T. ; Ritz, S. ; Rodriguez, A. Y. ; Romani, R. W. ; Roth, M. ; Ryde, F. ; Sadrozinski, H. F W ; Sanchez, D. ; Sander, A. ; Saz Parkinson, P. M. ; Scargle, J. D. ; Schalk, T. L. ; Sgrò, C. ; Siskind, E. J. ; Smith, D. A. ; Smith, P. D. ; Spandre, G. ; Spinelli, P. ; Strickman, M. S. ; Suson, D. J. ; Tajima, H. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. B. ; Thayer, J. G. ; Thompson, D. J. ; Tibaldo, L. ; Tibolla, O. ; Torres, D. F. ; Tosti, G. ; Tramacere, A. ; Uchiyama, Y. ; Usher, T. L. ; Vasileiou, V. ; Venter, C. ; Vilchez, N. ; Vitale, V. ; Waite, A. P. ; Wang, P. ; Winer, B. L. ; Wood, K. S. ; Yamazaki, R. ; Ylinen, T. ; Ziegler, M. / Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C. In: Astrophysical Journal. 2009 ; Vol. 706, No. 1 PART 2.
    @article{26480e57ef514a54866a6fe21867d224,
    title = "Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C",
    abstract = "The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (104 yr) ∼ with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 × 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral π mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to ̄n H Wp ≃ 5× 1051 (D/6kpc)2 erg cm-2. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.",
    keywords = "Acceleration of particles, ISM: individual (W51C), Radiation mechanisms: non-thermal",
    author = "Abdo, {A. A.} and M. Ackermann and M. Ajello and L. Baldini and J. Ballet and G. Barbiellini and Baring, {M. G.} and D. Bastieri and Baughman, {B. M.} and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and A. Bouvier and J. Bregeon and A. Brez and M. Brigida and P. Bruel and Burnett, {T. H.} 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 A. Chekhtman and Cheung, {C. C.} and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and Cominsky, {L. R.} and J. Conrad and S. Cutini and Dermer, {C. D.} and {De Angelis}, A. and {De Palma}, F. and Digel, {S. W.} and M. Dormody and {Do Couto E Silva}, E. and Drell, {P. S.} and R. Dubois and D. Dumora and C. Farnier and C. Favuzzi and Fegan, {S. J.} and Focke, {W. B.} and P. Fortin and M. Frailis and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and S. Germani and G. Giavitto and B. Giebels and N. Giglietto and F. Giordano and T. Glanzman and G. Godfrey and Grenier, {I. A.} and Grondin, {M. H.} and Grove, {J. E.} and L. Guillemot and S. Guiriec and Y. Hanabata and Harding, {A. K.} and M. Hayashida and E. Hays and Hughes, {R. E.} and Jackson, {M. S.} and G. J{\'o}hannesson and Johnson, {A. S.} and Johnson, {T. J.} and Johnson, {W. N.} and T. Kamae and H. Katagiri and Jun Kataoka and J. Katsuta and N. Kawai and M. Kerr and J. Kn{\"o}dlseder and Kocian, {M. L.} and M. Kuss and J. Lande and L. Latronico and M. Lemoine-Goumard and F. Longo and F. Loparco and B. Lott and Lovellette, {M. N.} and P. Lubrano and A. Makeev and Mazziotta, {M. N.} and McEnery, {J. E.} and C. Meurer and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and Moiseev, {A. A.} and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and T. Nakamori and Nolan, {P. L.} and Norris, {J. P.} and E. Nuss and T. Ohsugi and A. Okumura and N. Omodei and E. Orlando and Ormes, {J. F.} and D. Paneque and D. Parent and V. Pelassa and M. Pepe and M. Pesce-Rollins and F. Piron and Porter, {T. A.} and S. Rain{\`o} and R. Rando and M. Razzano and A. Reimer and O. Reimer and T. Reposeur and S. Ritz and Rodriguez, {A. Y.} and Romani, {R. W.} and M. Roth and F. Ryde and Sadrozinski, {H. F W} and D. Sanchez and A. Sander and {Saz Parkinson}, {P. M.} and Scargle, {J. D.} and Schalk, {T. L.} and C. Sgr{\`o} and Siskind, {E. J.} and Smith, {D. A.} and Smith, {P. D.} and G. Spandre and P. Spinelli and Strickman, {M. S.} and Suson, {D. J.} and H. Tajima and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. B.} and Thayer, {J. G.} and Thompson, {D. J.} and L. Tibaldo and O. Tibolla and Torres, {D. F.} and G. Tosti and A. Tramacere and Y. Uchiyama and Usher, {T. L.} and V. Vasileiou and C. Venter and N. Vilchez and V. Vitale and Waite, {A. P.} and P. Wang and Winer, {B. L.} and Wood, {K. S.} and R. Yamazaki and T. Ylinen and M. Ziegler",
    year = "2009",
    doi = "10.1088/0004-637X/706/1/L1",
    language = "English",
    volume = "706",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "1 PART 2",

    }

    TY - JOUR

    T1 - Fermi lat discovery of extended gamma-ray emission in the direction of supernova remnant W51C

    AU - Abdo, A. A.

    AU - Ackermann, M.

    AU - Ajello, M.

    AU - Baldini, L.

    AU - Ballet, J.

    AU - Barbiellini, G.

    AU - Baring, M. G.

    AU - Bastieri, D.

    AU - Baughman, B. M.

    AU - Bechtol, K.

    AU - Bellazzini, R.

    AU - Berenji, B.

    AU - Blandford, R. D.

    AU - Bloom, E. D.

    AU - Bonamente, E.

    AU - Borgland, A. W.

    AU - Bouvier, A.

    AU - Bregeon, J.

    AU - Brez, A.

    AU - Brigida, M.

    AU - Bruel, P.

    AU - Burnett, T. H.

    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 - Chekhtman, A.

    AU - Cheung, C. C.

    AU - Chiang, J.

    AU - Ciprini, S.

    AU - Claus, R.

    AU - Cohen-Tanugi, J.

    AU - Cominsky, L. R.

    AU - Conrad, J.

    AU - Cutini, S.

    AU - Dermer, C. D.

    AU - De Angelis, A.

    AU - De Palma, F.

    AU - Digel, S. W.

    AU - Dormody, M.

    AU - Do Couto E Silva, E.

    AU - Drell, P. S.

    AU - Dubois, R.

    AU - Dumora, D.

    AU - Farnier, C.

    AU - Favuzzi, C.

    AU - Fegan, S. J.

    AU - Focke, W. B.

    AU - Fortin, P.

    AU - Frailis, M.

    AU - Fukazawa, Y.

    AU - Funk, S.

    AU - Fusco, P.

    AU - Gargano, F.

    AU - Gasparrini, D.

    AU - Gehrels, N.

    AU - Germani, S.

    AU - Giavitto, G.

    AU - Giebels, B.

    AU - Giglietto, N.

    AU - Giordano, F.

    AU - Glanzman, T.

    AU - Godfrey, G.

    AU - Grenier, I. A.

    AU - Grondin, M. H.

    AU - Grove, J. E.

    AU - Guillemot, L.

    AU - Guiriec, S.

    AU - Hanabata, Y.

    AU - Harding, A. K.

    AU - Hayashida, M.

    AU - Hays, E.

    AU - Hughes, R. E.

    AU - Jackson, M. S.

    AU - Jóhannesson, G.

    AU - Johnson, A. S.

    AU - Johnson, T. J.

    AU - Johnson, W. N.

    AU - Kamae, T.

    AU - Katagiri, H.

    AU - Kataoka, Jun

    AU - Katsuta, J.

    AU - Kawai, N.

    AU - Kerr, M.

    AU - Knödlseder, J.

    AU - Kocian, M. L.

    AU - Kuss, M.

    AU - Lande, J.

    AU - Latronico, L.

    AU - Lemoine-Goumard, M.

    AU - Longo, F.

    AU - Loparco, F.

    AU - Lott, B.

    AU - Lovellette, M. N.

    AU - Lubrano, P.

    AU - Makeev, A.

    AU - Mazziotta, M. N.

    AU - McEnery, J. E.

    AU - Meurer, C.

    AU - Michelson, P. F.

    AU - Mitthumsiri, W.

    AU - Mizuno, T.

    AU - Moiseev, A. A.

    AU - Monte, C.

    AU - Monzani, M. E.

    AU - Morselli, A.

    AU - Moskalenko, I. V.

    AU - Murgia, S.

    AU - Nakamori, T.

    AU - Nolan, P. L.

    AU - Norris, J. P.

    AU - Nuss, E.

    AU - Ohsugi, T.

    AU - Okumura, A.

    AU - Omodei, N.

    AU - Orlando, E.

    AU - Ormes, J. F.

    AU - Paneque, D.

    AU - Parent, D.

    AU - Pelassa, V.

    AU - Pepe, M.

    AU - Pesce-Rollins, M.

    AU - Piron, F.

    AU - Porter, T. A.

    AU - Rainò, S.

    AU - Rando, R.

    AU - Razzano, M.

    AU - Reimer, A.

    AU - Reimer, O.

    AU - Reposeur, T.

    AU - Ritz, S.

    AU - Rodriguez, A. Y.

    AU - Romani, R. W.

    AU - Roth, M.

    AU - Ryde, F.

    AU - Sadrozinski, H. F W

    AU - Sanchez, D.

    AU - Sander, A.

    AU - Saz Parkinson, P. M.

    AU - Scargle, J. D.

    AU - Schalk, T. L.

    AU - Sgrò, C.

    AU - Siskind, E. J.

    AU - Smith, D. A.

    AU - Smith, P. D.

    AU - Spandre, G.

    AU - Spinelli, P.

    AU - Strickman, M. S.

    AU - Suson, D. J.

    AU - Tajima, H.

    AU - Takahashi, H.

    AU - Takahashi, T.

    AU - Tanaka, T.

    AU - Thayer, J. B.

    AU - Thayer, J. G.

    AU - Thompson, D. J.

    AU - Tibaldo, L.

    AU - Tibolla, O.

    AU - Torres, D. F.

    AU - Tosti, G.

    AU - Tramacere, A.

    AU - Uchiyama, Y.

    AU - Usher, T. L.

    AU - Vasileiou, V.

    AU - Venter, C.

    AU - Vilchez, N.

    AU - Vitale, V.

    AU - Waite, A. P.

    AU - Wang, P.

    AU - Winer, B. L.

    AU - Wood, K. S.

    AU - Yamazaki, R.

    AU - Ylinen, T.

    AU - Ziegler, M.

    PY - 2009

    Y1 - 2009

    N2 - The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (104 yr) ∼ with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 × 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral π mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to ̄n H Wp ≃ 5× 1051 (D/6kpc)2 erg cm-2. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.

    AB - The discovery of bright gamma-ray emission coincident with supernova remnant (SNR) W51C is reported using the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. W51C is a middle-aged remnant (104 yr) ∼ with intense radio synchrotron emission in its shell and known to be interacting with a molecular cloud. The gamma-ray emission is spatially extended, broadly consistent with the radio and X-ray extent of SNR W51C. The energy spectrum in the 0.2-50 GeV band exhibits steepening toward high energies. The luminosity is greater than 1 × 1036 erg s-1 given the distance constraint of D > 5.5 kpc, which makes this object one of the most luminous gamma-ray sources in our Galaxy. The observed gamma-rays can be explained reasonably by a combination of efficient acceleration of nuclear cosmic rays at supernova shocks and shock-cloud interactions. The decay of neutral π mesons produced in hadronic collisions provides a plausible explanation for the gamma-ray emission. The product of the average gas density and the total energy content of the accelerated protons amounts to ̄n H Wp ≃ 5× 1051 (D/6kpc)2 erg cm-2. Electron density constraints from the radio and X-ray bands render it difficult to explain the LAT signal as due to inverse Compton scattering. The Fermi LAT source coincident with SNR W51C sheds new light on the origin of Galactic cosmic rays.

    KW - Acceleration of particles

    KW - ISM: individual (W51C)

    KW - Radiation mechanisms: non-thermal

    UR - http://www.scopus.com/inward/record.url?scp=77749266344&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=77749266344&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/706/1/L1

    DO - 10.1088/0004-637X/706/1/L1

    M3 - Article

    VL - 706

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 1 PART 2

    ER -