The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
Abstract
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 and a break energy of GeV using our baseline diffuse Galactic emission model. The total intensity attributed to the IGRB is cm s sr above 100 MeV, with an additional %/% systematic uncertainty due to the Galactic diffuse foregrounds.
Keywords
Cite
@article{arxiv.1410.3696,
title = {The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV},
author = {The Fermi LAT collaboration and M. Ackermann and M. Ajello and A. Albert and W. B. Atwood and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and K. Bechtol and R. Bellazzini and E. Bissaldi and R. D. Blandford and E. D. Bloom and E. Bottacini and T. J. Brandt and J. Bregeon and P. Bruel and R. Buehler and S. Buson and G. A. Caliandro and R. A. Cameron and M. Caragiulo and P. A. Caraveo and E. Cavazzuti and C. Cecchi and E. Charles and A. Chekhtman and J. Chiang and G. Chiaro and S. Ciprini and R. Claus and J. Cohen-Tanugi and J. Conrad and A. Cuoco and S. Cutini and F. D'Ammando and A. de Angelis and F. de Palma and C. D. Dermer and S. W. Digel and E. do Couto e Silva and P. S. Drell and C. Favuzzi and E. C. Ferrara and W. B. Focke and A. Franckowiak and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and S. Germani and N. Giglietto and P. Giommi and F. Giordano and M. Giroletti and G. Godfrey and G. A. Gomez-Vargas and I. A. Grenier and S. Guiriec and M. Gustafsson and D. Hadasch and K. Hayashi and E. Hays and J. W. Hewitt and P. Ippoliti and T. Jogler and G. Jóhannesson and A. S. Johnson and W. N. Johnson and T. Kamae and J. Kataoka and J. Knödlseder and M. Kuss and S. Larsson and L. Latronico and J. Li and L. Li and F. Longo and F. Loparco and B. Lott and M. N. Lovellette and P. Lubrano and G. M. Madejski and A. Manfreda and F. Massaro and M. Mayer and M. N. Mazziotta and J. E. McEnery and P. F. Michelson and W. Mitthumsiri and T. Mizuno and A. A. Moiseev and M. E. Monzani and A. Morselli and I. V. Moskalenko and S. Murgia and R. Nemmen and E. Nuss and T. Ohsugi and N. Omodei and E. Orlando and J. F. Ormes and D. Paneque and J. H. Panetta and J. S. Perkins and M. Pesce-Rollins and F. Piron and G. Pivato and T. A. Porter and S. Rainò and R. Rando and M. Razzano and S. Razzaque and A. Reimer and O. Reimer and T. Reposeur and S. Ritz and R. W. Romani and M. Sánchez-Conde and M. Schaal and A. Schulz and C. Sgrò and E. J. Siskind and G. Spandre and P. Spinelli and A. W. Strong and D. J. Suson and H. Takahashi and J. G. Thayer and J. B. Thayer and L. Tibaldo and M. Tinivella and D. F. Torres and G. Tosti and E. Troja and Y. Uchiyama and G. Vianello and M. Werner and B. L. Winer and K. S. Wood and M. Wood and G. Zaharijas and S. Zimmer},
journal= {arXiv preprint arXiv:1410.3696},
year = {2015}
}
Comments
Accepted by The Astrophysical Journal