The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z similar to 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.
The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars / Ackermann M; Ajello M; Allafort A; Schady P; Baldini L; Ballet J; Barbiellini G; Bastieri D; Bellazzini R; Blandford RD; Bloom ED; Borgland AW; Bottacini E; Bouvier A; Bregeon J; Brigida M; Bruel P; Buehler R; Buson S; Caliandro GA; Cameron RA; Caraveo PA; Cavazzuti E; Cecchi C; Charles E; Chaves RCG; Chekhtman A; Cheung CC; Chiang J; Chiaro G; Ciprini S; Claus R; Cohen-Tanugi J; Conrad J; Cutini S; DAmmando F; de Palma F; Dermer CD; Digel SW; Silva EDE; Domnguez A; Drell PS; Drlica-Wagner A; Favuzzi C; Fegan SJ; Focke WB; Franckowiak A; Fukazawa Y; Funk S; Fusco P; Gargano F; Gasparrini D; Gehrels N; Germani S; Giglietto N; Giordano F; Giroletti M; Glanzman T; Godfrey G; Grenier IA; Grove JE; Guiriec S; Gustafsson M; Hadasch D; Hayashida M; Hays E; Jackson MS; Jogler T; Kataoka J; Knodlseder J; Kuss M; Lande J; Larsson S; Latronico L; Longo F; Loparco F; Lovellette MN; Lubrano P; Mazziotta MN; McEnery JE; Mehault J; Michelson PF; Mizuno T; Monte C; Monzani ME; Morselli A; Moskalenko IV; Murgia S; Tramacere A; Nuss E; Greiner J; Ohno M; Ohsugi T; Omodei N; Orienti M; Orlando E; Ormes JF; Paneque D; Perkins JS; Pesce-Rollins M; Piron F; Pivato G; Porter TA; Raino S; Rando R; Razzano M; Razzaque S; Reimer A; Reimer O; Reyes LC; Ritz S; Rau A; Romoli C; Roth M; Sanchez-Conde M; Sanchez DA; Scargle JD; Sgro C; Siskind EJ; Spandre G; Spinelli P; Stawarz L; Suson DJ; Takahashi H; Tanaka T; Thayer JG; Thompson DJ; Tibaldo L; Tinivella M; Torres DF; Tosti G; Troja E; Usher TL; Vandenbroucke J; Vasileiou V; Vianello G; Vitale V; Waite AP; Winer BL; Wood KS; Wood M. - In: SCIENCE. - ISSN 0036-8075. - STAMPA. - 338:6111(2012), pp. 1190-1192. [10.1126/science.1227160]
The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars
D'AMMANDO, FILIPPO;
2012
Abstract
The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z similar to 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
