The MAGIC telescopes discovered very high energy ( VHE , E > 100 GeV ) gamma-ray emission coming from the distant Flat Spectrum Radio Quasar ( FSRQ ) PKS 1222+21 ( 4C +21.35 , z=0.432 ) .
It is the second most distant VHE gamma-ray source , with well measured redshift , detected until now .
The observation was performed on 2010 June 17 ( MJD 55364.9 ) using the two 17 m diameter imaging Cherenkov telescopes on La Palma ( Canary Islands , Spain ) .
The MAGIC detection coincides with high energy MeV/GeV gamma-ray activity measured by the Large Area Telescope ( LAT ) on board the Fermi satellite .
The averaged integral flux above 100 GeV is equivalent to 1 Crab Nebula flux .
The VHE flux measured by MAGIC varies significantly within the 30 minutes of exposure implying a flux doubling time of about 10 minutes .
The VHE and MeV/GeV spectra , corrected for the absorption by the extragalactic background light , can be described by a single power law with photon index 2.72 \pm 0.34 between 3 GeV and 400 GeV , consistent with gamma-ray emission belonging to a single component in the jet .
The absence of a spectral cutoff at 30-60 GeV ( indeed , one finds a strict lower limit E _ { c } > 130 GeV ) constrains the gamma-ray emission region to lie outside the broad line region , which would otherwise absorb the VHE gamma-rays .
Together with the detected fast variability , this challenges present emission models from jets in FSRQs .