Skip to main content
Article thumbnail
Location of Repository

DEVELOPMENT of the MODEL of GALACTIC INTERSTELLAR EMISSION for STANDARD POINT-SOURCE ANALYSIS of FERMI LARGE AREA TELESCOPE DATA

By F. Acero, M. Ackermann, M. Ajello, A. Albert, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, E.D. Bloom, R. Bonino, E. Bottacini, T.J. Brandt, J. Bregeon, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, M. Caragiulo, P.A. Caraveo, J.M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, G. Chiaro, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, A. Cuoco, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, R. Desiante, S.W. Digel, L. Di Venere, P.S. Drell, C. Favuzzi, S.J. Fegan, E.C. Ferrara, W.B. Focke, A. Franckowiak, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I.A. Grenier, S. Guiriec, D. Hadasch, A.K. Harding, K. Hayashi, E. Hays, J.W. Hewitt, A.B. Hill, D. Horan, X. Hou, T. Jogler, G. Jóhannesson, T. Kamae, M. Kuss, D. Landriu, S. Larsson, L. Latronico, J. Li, L. Li, F. Longo, F. Loparco, M.N. Lovellette, P. Lubrano, S. Maldera, D. Malyshev, A. Manfreda, P. Martin, M. Mayer, M.N. Mazziotta, J.E. Mcenery, P.F. Michelson, N. Mirabal, T. Mizuno, M.E. Monzani, A. Morselli, E. Nuss, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, J.F. Ormes, D. Paneque, M. Pesce-Rollins, F. Piron, G. Pivato, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, Q. Remy, N. Renault, M. Sánchez-Conde, M. Schaal, A. Schulz, C. Sgrò, E.J. Siskind, F. Spada, G. Spandre, P. Spinelli, A.W. Strong, D.J. Suson, H. Tajima, H. Takahashi, J.B. Thayer, D.J. Thompson, L. Tibaldo, M. Tinivella, D.F. Torres, G. Tosti, E. Troja, G. Vianello, M. Werner, K.S. Wood, M. Wood, G. Zaharijas and S. Zimmer

Abstract

Most of the celestial γ rays detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point-source and extended-source studies rely on the modeling of this diffuse emission for accurate characterization. Here, we describe the development of the Galactic Interstellar Emission Model (GIEM), which is the standard adopted by the LAT Collaboration and is publicly available. This model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission produced in the Galaxy. In the GIEM, we also include large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20° and we observe an enhanced emission toward their base extending in the north and south Galactic directions and located within ˜4° of the Galactic Center

Topics: gamma rays: diffuse background, gamma rays: general, gamma rays: ISM, Astronomy and Astrophysics, Space and Planetary Science
Year: 2016
DOI identifier: 10.3847/0067-0049
OAI identifier: oai:arts.units.it:11368/2898543
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://iopscience.iop.org/arti... (external link)
  • http://hdl.handle.net/11368/28... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.