Publication Date:
2010-01-09
Description:
Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~10(15) electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 x 10(8) electron volts and 3 x10(11) electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above approximately 10(9) electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉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 -- 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 -- Celik, O -- Chekhtman, A -- Cheung, C C -- Chiang, J -- Ciprini, S -- Claus, R -- Cognard, I -- Cohen-Tanugi, J -- Cominsky, L R -- Conrad, J -- Cutini, S -- Dermer, C D -- de Angelis, A -- de Palma, F -- Digel, S W -- do Couto e Silva, E -- Drell, P S -- Dubois, R -- Dumora, D -- Espinoza, C -- 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 -- Johannesson, G -- Johnson, A S -- Johnson, T J -- Johnson, W N -- Kamae, T -- Katagiri, H -- Kataoka, J -- Katsuta, J -- Kawai, N -- Kerr, M -- Knodlseder, J -- Kocian, M L -- Kramer, M -- Kuss, M -- Lande, J -- Latronico, L -- Lemoine-Goumard, M -- Longo, F -- Loparco, F -- Lott, B -- Lovellette, M N -- Lubrano, P -- Lyne, A G -- Madejski, G M -- Makeev, A -- Mazziotta, M N -- McEnery, J E -- Meurer, C -- Michelson, P F -- Mitthumsiri, W -- Mizuno, T -- Monte, C -- Monzani, M E -- Morselli, A -- Moskalenko, I V -- Murgia, S -- Nakamori, T -- Nolan, P L -- Norris, J P -- Noutsos, A -- Nuss, E -- Ohsugi, T -- Omodei, N -- Orlando, E -- Ormes, J F -- Paneque, D -- Parent, D -- Pelassa, V -- Pepe, M -- Pesce-Rollins, M -- Piron, F -- Porter, T A -- Raino, S -- Rando, R -- Razzano, M -- Reimer, A -- Reimer, O -- Reposeur, T -- Rochester, L 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 -- Sgro, C -- Siskind, E J -- Smith, D A -- Smith, P D -- Spandre, G -- Spinelli, P -- Stappers, B W -- Stecker, F W -- Strickman, M S -- Suson, D J -- Tajima, H -- Takahashi, H -- Takahashi, T -- Tanaka, T -- Thayer, J B -- Thayer, J G -- Theureau, 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 -- New York, N.Y. -- Science. 2010 Feb 26;327(5969):1103-6. doi: 10.1126/science.1182787. Epub 2010 Jan 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20056857" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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