Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes

Abdo, Aa; Ackermann, M; Ajello, M; Anderson, B; Atwood, Wb; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, Bm; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, Rd; Bloom, Ed; Bonamente, E; Borgland, Aw; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, Th; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Casandjian, Jm; Cecchi, C; Charles, E; Chekhtman, A; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Dereli, H; Dermer, Cd; De Angelis, A; De Palma, F; Digel, Sw; Di Bernardo, G; Dormody, M; Ede, Silva; Drell, Ps; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Favuzzi, Cecilia; Fegan, Sj; Focke, Wb; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gaggero, D; Gargano, F; Gehrels, N; Germani, S; Giebels, B; Giglietto, Nicola; Giordano, F; Glanzman, T; Godfrey, G; Grenier, Ia; Grondin, Mh; Grove, Je; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, Ak; Hayashida, M; Hays, E; Hughes, Re; Johannesson, G; Johnson, As; Johnson, Rp; Johnson, Tj; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knodlseder, J; Kocian, Ml; Kuehn, F; Kuss, M; Lande, J; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, Mn; Lubrano, P; Madejski, Gm; Makeev, A; Mazziotta, Mn; Mcconville, W; Mcenery, Je; Meurer, C; Michelson, Pf; Mitthumsiri, W; Mizuno, T; Moiseev, Aa; Monte, C; Monzani, Me; Morselli, A; Moskalenko, Iv; Murgia, S; Nolan, Pl; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf; Paneque, D; Panetta, Jh; Parent, D; Pelassa, V; Pepe, M; Pesce Rollins, M; Piron, F; Porter, Ta; Raino, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rodriguez, Ay; Roth, M; Ryde, F; Hfw, Sadrozinski; Sanchez, D; Sander, A; Pms, Parkinson; Scargle, Jd; Sellerholm, A; Sgro, C; Smith, Da; Smith, Pd; Spandre, G; Spinelli, P; Starck, Jl; Stecker, Fw; Striani, E; Strickman, Ms; Strong, Aw; Suson, Dj; Tajima, H; Takahashi, H; Tanaka, T; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vasileiou, V; Vilchez, N; Vitale, V; Waite, Ap; Wang, P; Winer, Bl; Wood, Ks; Ylinen, T; Ziegler, M.

doi:10.1103/PhysRevLett.103.251101

The diffuse galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess gamma-ray emission greater than or similar to 1 GeV relative to diffuse galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called "EGRET GeV excess"). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10 degrees <|b|< 20 degrees. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes / Abdo, A.a., Ackermann, M., Ajello, M., Anderson, B., Atwood, W.b., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, 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., et al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 103:25(2009). [10.1103/PhysRevLett.103.251101]