%0 Journal Article
%T The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
%A The Fermi LAT collaboration
%A M. Ackermann
%A M. Ajello
%A A. Albert
%A W. B. Atwood
%A L. Baldini
%A J. Ballet
%A G. Barbiellini
%A D. Bastieri
%A K. Bechtol
%A R. Bellazzini
%A E. Bissaldi
%A R. D. Blandford
%A E. D. Bloom
%A E. Bottacini
%A T. J. Brandt
%A J. Bregeon
%A P. Bruel
%A R. Buehler
%A S. Buson
%A G. A. Caliandro
%A R. A. Cameron
%A M. Caragiulo
%A P. A. Caraveo
%A E. Cavazzuti
%A C. Cecchi
%A E. Charles
%A A. Chekhtman
%A J. Chiang
%A G. Chiaro
%A S. Ciprini
%A R. Claus
%A J. Cohen-Tanugi
%A J. Conrad
%A A. Cuoco
%A S. Cutini
%A F. D'Ammando
%A A. de Angelis
%A F. de Palma
%A C. D. Dermer
%A S. W. Digel
%A E. do Couto e Silva
%A P. S. Drell
%A C. Favuzzi
%A E. C. Ferrara
%A W. B. Focke
%A A. Franckowiak
%A Y. Fukazawa
%A S. Funk
%A P. Fusco
%A F. Gargano
%A D. Gasparrini
%A S. Germani
%A N. Giglietto
%A P. Giommi
%A F. Giordano
%A M. Giroletti
%A G. Godfrey
%A G. A. Gomez-Vargas
%A I. A. Grenier
%A S. Guiriec
%A M. Gustafsson
%A D. Hadasch
%A K. Hayashi
%A E. Hays
%A J. W. Hewitt
%A P. Ippoliti
%A T. Jogler
%A G. J¨®hannesson
%A A. S. Johnson
%A W. N. Johnson
%A T. Kamae
%A J. Kataoka
%A J. Kn£¿dlseder
%A M. Kuss
%A S. Larsson
%A L. Latronico
%A J. Li
%A L. Li
%A F. Longo
%A F. Loparco
%A B. Lott
%A M. N. Lovellette
%A P. Lubrano
%A G. M. Madejski
%A A. Manfreda
%A F. Massaro
%A M. Mayer
%A M. N. Mazziotta
%A J. E. McEnery
%A P. F. Michelson
%A W. Mitthumsiri
%A T. Mizuno
%A A. A. Moiseev
%A M. E. Monzani
%A A. Morselli
%A I. V. Moskalenko
%A S. Murgia
%A R. Nemmen
%A E. Nuss
%A T. Ohsugi
%A N. Omodei
%A E. Orlando
%A J. F. Ormes
%A D. Paneque
%A J. H. Panetta
%A J. S. Perkins
%A M. Pesce-Rollins
%A F. Piron
%A G. Pivato
%A T. A. Porter
%A S. Rain¨°
%A R. Rando
%A M. Razzano
%A S. Razzaque
%A A. Reimer
%A O. Reimer
%A T. Reposeur
%A S. Ritz
%A R. W. Romani
%A M. S¨¢nchez-Conde
%A M. Schaal
%A A. Schulz
%A C. Sgr¨°
%J Physics
%D 2014
%I arXiv
%R 10.1088/0004-637X/799/1/86
%X The {\gamma}-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 {\gamma}-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, 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 $2.32\pm0.02$ and a break energy of $(279\pm52)$ GeV using our baseline diffuse Galactic emission model. The total intensity attributed to the IGRB is $(7.2\pm0.6) \times 10^{-6}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$ above 100 MeV, with an additional $+15$%/$-30$% systematic uncertainty due to the Galactic diffuse foregrounds.
%U http://arxiv.org/abs/1410.3696v1