Discovery of very high energy gamma-rays from the flat spectrum radio quasar 3C 279 with the MAGIC telescope

摘要

3C 279 is one of the best studied flat spectrum radio quasars located at a comparatively large redshift of z = 0.536.Observations in the very high energy band of such distant sources were impossible until recently due to the expected steepenergy spectrum and the strong gamma-ray attenuation by the extragalactic background light photon field, which conspireto make the source visible only with a low energy threshold. Here the detection of a significant gamma ray signal from3C 279 at very high energies (E > 75 GeV) during a flare in early 2006 is reported. Implications of its energy spectrum on thecurrent understanding of the extragalactic background light and very high energy gamma-ray emission mechanism models arediscussed.