Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV

Ackermann, M; Ajello, M; Atwood, Wb; Baldini, Luca; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, Bm; Bechtol, K; Bellardi, F; Bellazzini, R; Belli, F; Berenji, B; Blandford, Rd; Bloom, Ed; Bogart, Jr; Bonamente, E; Borgland, Aw; Brandt, Tj; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Burnett, Th; Busetto, G; Buson, S; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Carlson, P; Carrigan, S; Casandjian, Jm; Ceccanti, M; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, Cc; Chiang, J; Cillis, An; Ciprini, S; Claus, R; Cohen Tanugi, J; Conrad, J; Corbet, R; Deklotz, M; Dermer, Cd; de Angelis, A; de Palma, F; Digel, Sw; Di Bernardo, G; Ede, Silva; Drell, Ps; Drlica Wagner, A; Dubois, R; Fabiani, D; Favuzzi, C; Fegan, Sj; Fortin, P; Fukazawa, Y; Funk, S; Fusco, P; Gaggero, D; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grasso, D; Grenier, Ia; Grondin, Mh; Grove, Je; Guiriec, S; Gustafsson, M; Hadasch, D; Harding, Ak; Hayashida, M; Hays, E; Horan, D; Hughes, Re; Johannesson, G; Johnson, As; Johnson, Rp; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knodlseder, J; Kuss, M; Lande, J; Latronico, L; Lemoine Goumard, M; Garde, Ml; Longo, F; Loparco, F; Lott, B; Lovellette, Mn; Lubrano, P; Makeev, A; Mazziotta, Mn; Mcenery, Je; Mehault, J; Michelson, Pf; Minuti, M; Mitthumsiri, W; Mizuno, T; Moiseev, Aa; Monte, C; Monzani, Me; Moretti, E; Morselli, A; Moskalenko, Iv; Murgia, S; Nakamori, T; Naumann Godo, M; Nolan, Pl; Norris, Jp; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, Jf; Ozaki, M; Paneque, D; Panetta, Jh; Parent, D; Pelassa, V; Pepe, M; Pesce Rollins, M; Petrosian, V; Pinchera, M; Piron, F; Porter, Ta; Profumo, S; Raino, S; Rando, R; Rapposelli, E; Razzano, Massimiliano; Reimer, A; Reimer, O; Reposeur, T; Ripken, J; Ritz, S; Rochester, Ls; Romani, Rw; Roth, M; Hfw, Sadrozinski; Saggini, N; Sanchez, D; Sander, A; Sgro, C; Siskind, Ej; Smith, Pd; Spandre, G; Spinelli, P; Stawarz, L; Stephens, Te; Strickman, Ms; Strong, Aw; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Tibolla, O; Torres, Df; Tosti, G; Tramacere, A; Turri, M; Uchiyama, Y; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vilchez, N; Vitale, V; Waite, Ap; Wallace, E; Wang, P; Winer, Bl; Wood, Ks; Yang, Z; Ylinen, T; Ziegler, M.

doi:10.1103/PhysRevD.82.092004

We present the results of our analysis of cosmic-ray electrons using about 8×106 electron candidates detected in the first 12 months on-orbit by the Fermi Large Area Telescope. This work extends our previously published cosmic-ray electron spectrum down to 7 GeV, giving a spectral range of approximately 2.5 decades up to 1 TeV. We describe in detail the analysis and its validation using beam-test and on-orbit data. In addition, we describe the spectrum measured via a subset of events selected for the best energy resolution as a cross-check on the measurement using the full event sample. Our electron spectrum can be described with a power law ∝E-3.08±0.05 with no prominent spectral features within systematic uncertainties. Within the limits of our uncertainties, we can accommodate a slight spectral hardening at around 100 GeV and a slight softening above 500 GeV.