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http://hdl.handle.net/20.500.12386/24242
Title: | The Spectrum of Isotropic Diffuse Gamma-Ray Emission between 100 MeV and 820 GeV | Authors: | Ackermann, M. Ajello, M. Albert, A. Atwood, W. B. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Bechtol, K. Bellazzini, R. Bissaldi, E. Blandford, R. D. Bloom, E. D. Bottacini, E. Brandt, T. J. Bregeon, J. Bruel, P. Buehler, R. Buson, S. Caliandro, G. A. Cameron, R. A. Caragiulo, M. CARAVEO, PATRIZIA Cavazzuti, E. Cecchi, C. Charles, E. Chekhtman, A. Chiang, J. Chiaro, G. Ciprini, S. Claus, R. Cohen-Tanugi, J. Conrad, J. Cuoco, A. Cutini, S. D'AMMANDO, FILIPPO de Angelis, A. de Palma, F. Dermer, C. D. Digel, S. W. Silva, E. do Couto e. Drell, P. S. Favuzzi, C. Ferrara, E. C. Focke, W. B. Franckowiak, A. Fukazawa, Y. Funk, S. Fusco, P. Gargano, F. Gasparrini, D. Germani, S. Giglietto, N. GIROLETTI, MARCELLO Giordano, F. Giroletti, M. Godfrey, G. Gomez-Vargas, G. A. Grenier, I. A. Guiriec, S. Gustafsson, M. Hadasch, D. Hayashi, K. Hays, E. Hewitt, J. W. Ippoliti, P. Jogler, T. Jóhannesson, G. Johnson, A. S. Johnson, W. N. Kamae, T. Kataoka, J. Knödlseder, J. Kuss, M. Larsson, S. Latronico, L. Li, J. Li, L. Longo, F. Loparco, F. Lott, B. Lovellette, M. N. Lubrano, P. Madejski, G. M. Manfreda, A. Massaro, F. Mayer, M. Mazziotta, M. N. McEnery, J. E. Michelson, P. F. Mitthumsiri, W. Mizuno, T. Moiseev, A. A. Monzani, M. E. Morselli, A. Moskalenko, I. V. Murgia, S. Nemmen, R. Nuss, E. Ohsugi, T. Omodei, N. Orlando, E. Ormes, J. F. Paneque, D. Panetta, J. H. Perkins, J. S. Pesce-Rollins, M. Piron, F. Pivato, G. Porter, T. A. Rainò, S. Rando, R. Razzano, M. Razzaque, S. Reimer, A. Reimer, O. Reposeur, T. Ritz, S. Romani, R. W. Sánchez-Conde, M. Schaal, M. Schulz, A. Sgrò, C. Siskind, E. J. Spandre, G. Spinelli, P. Strong, A. W. Suson, D. J. Takahashi, H. Thayer, J. G. Thayer, J. B. Tibaldo, L. Tinivella, M. Torres, D. F. Tosti, G. Troja, E. Uchiyama, Y. Vianello, G. Werner, M. Winer, B. L. Wood, K. S. Wood, M. Zaharijas, G. Zimmer, S. |
Issue Date: | 2015 | Journal: | THE ASTROPHYSICAL JOURNAL | Number: | 799 | Issue: | 1 | First Page: | 86 | Abstract: | The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, and a residual all-sky emission component commonly called the isotropic diffuse γ-ray background (IGRB). The IGRB comprises all extragalactic emissions too faint or too diffuse to be resolved in a given survey, as well as any residual Galactic foregrounds that are approximately isotropic. The first IGRB measurement with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi) used 10 months of sky-survey data and considered an energy range between 200 MeV and 100 GeV. Improvements in event selection and characterization of cosmic-ray backgrounds, better understanding of the diffuse Galactic emission (DGE), and a longer data accumulation of 50 months allow for a refinement and extension of the IGRB measurement with the LAT, now covering the energy range from 100 MeV to 820 GeV. The IGRB spectrum shows a significant high-energy cutoff feature and can be well described over nearly four decades in energy by a power law with exponential cutoff having a spectral index of 2.32 ± 0.02 and a break energy of (279 ± 52) GeV using our baseline DGE model. The total intensity attributed to the IGRB is (7.2 ± 0.6) × 10<SUP>-6</SUP> cm<SUP>-2</SUP> s<SUP>-1</SUP> sr<SUP>-1</SUP> above 100 MeV, with an additional +15%/-30% systematic uncertainty due to the Galactic diffuse foregrounds. | Acknowledgments: | The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT, as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States; the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK), and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Études Spatiales in France. GALPROP development is partially funded via NASA grant NNX09AC15G. Some of the results in this paper have been derived using the HEALPix (Górski et al. 2005 ) package. | URI: | http://hdl.handle.net/20.500.12386/24242 | URL: | https://iopscience.iop.org/article/10.1088/0004-637X/799/1/86 | ISSN: | 0004-637X | DOI: | 10.1088/0004-637X/799/1/86 | Bibcode ADS: | 2015ApJ...799...86A | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
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Ackermann_2015_ApJ_799_86.pdf | PDF editoriale | 3.26 MB | Adobe PDF | View/Open |
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