%0 Journal Article %A Antoranz Canales, Pedro %A Barrio Uña, Juan Abel %A Contreras González, José Luis %A Fonseca González, María Victoria %A Miranda Pantoja, José Miguel %A Nieto Castaño, Daniel %T Very-high-energy gamma rays from a distant quasar: how transparent is the universe? %D 2008 %@ 0036-8075 %U https://hdl.handle.net/20.500.14352/50832 %X The atmospheric Cherenkov gamma- ray telescope MAGIC, designed for a low- energy threshold, has detected very- high- energy gamma rays from a giant flare of the distant Quasi- Stellar Radio Source ( in short: radio quasar) 3C 279, at a distance of more than 5 billion light- years ( a redshift of 0.536). No quasar has been observed previously in very- high- energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high- energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts. %~