The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the γ-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of γ-ray blazars with redshift up to z ~ 3, and GRBs with redshift up to z ~ 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of γ-ray flux attenuation by the EBL. We place upper limits on the γ-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. can be ruled out with high confidence.

FERMI LARGE AREA TELESCOPE CONSTRAINTS ON THE GAMMA-RAY OPACITY OF THE UNIVERSE

BALDINI, LUCA;RAZZANO, MASSIMILIANO;
2010-01-01

Abstract

The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the γ-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of γ-ray blazars with redshift up to z ~ 3, and GRBs with redshift up to z ~ 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of γ-ray flux attenuation by the EBL. We place upper limits on the γ-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. can be ruled out with high confidence.
2010
Abdo, Aa; Ackermann, M; Ajello, M; Allafort, A; Atwood, Wb; Baldini, Luca; Ballet, J; Barbiellini, G; Baring, Mg; Bastieri, D; Baughman, Bm; Bechtol, K; Bellazzini, R; Berenji, B; Bhat, Pn; Blandford, Rd; Bloom, Ed; Bonamente, E; Borgland, Aw; Bouvier, A; Brandt, Tj; Bregeon, J; Brez, A; Briggs, Ms; Brigida, M; Bruel, P; Buehler, R; Burnett, Th; Buson, S; Caliandro, Ga; Cameron, Ra; Caraveo, Pa; Carrigan, S; Casandjian, Jm; Cavazzuti, E; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Chen, Aw; Cheung, Cc; Chiang, J; Ciprini, S; Claus, R; Cohen Tanugi, J; Connaughton, V; Conrad, J; Costamante, L; Dermer, Cd; de Angelis, A; de Palma, F; Digel, Sw; Dingus, Bl; Silva, Ede; Drell, Ps; Dubois, R; Favuzzi, C; Fegan, Sj; Finke, J; Fortin, P; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Gilmore, Rc; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Granot, J; Greiner, J; Grenier, Ia; Grove, Je; Guiriec, S; Gustafsson, M; Hadasch, D; Hayashida, M; Hays, E; Horan, D; Hughes, Re; Johannesson, G; Johnson, As; Johnson, Rp; Johnson, Wn; Kamae, T; Katagiri, H; Kataoka, J; Knodlseder, J; Kocevski, D; Kuss, M; Lande, J; Latronico, L; Lee, Sh; Garde, Ml; Longo, F; Loparco, F; Lott, B; Lovellette, Mn; Lubrano, P; Makeev, A; Mazziotta, N; Mcconville, W; Mcenery, Je; Mcglynn, S; Mehault, J; Meszaros, P; Michelson, Pf; 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; Ohno, M; 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; Piron, F; Porter, Ta; Primack, Jr; Raino, S; Rando, R; Razzano, Massimiliano; Razzaque, S; Reimer, A; Reimer, O; Reyes, Lc; Ripken, J; Ritz, S; Romani, Rw; Roth, M; Sadrozinski, Hfw; Sanchez, D; Sander, A; Scargle, Jd; Schalk, Tl; Sgro, C; Shaw, Ms; Siskind, Ej; Smith, Pd; Spandre, G; Spinelli, P; Stecker, Fw; Strickman, Ms; Suson, Dj; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, Jb; Thayer, Jg; Thompson, Dj; Tibaldo, L; Torres, Df; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, Tl; Vandenbroucke, J; Vasileiou, V; Vilchez, N; Vitale, V; von Kienlin, A; Waite, Ap; Wang, P; Wilson Hodge, C; Winer, Bl; Wood, Ks; Yamazaki, R; Yang, Z; Ylinen, T; Ziegler, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/193778
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