A deep observation campaign carried out by the High Energy Stereoscopic System ( H.E.S.S . )
on Centaurus A enabled the discovery of \gamma rays from the blazar 1ES 1312 - 423 , 2 ^ { \circ } away from the radio galaxy .
With a differential flux at 1 TeV of \phi ( 1 TeV ) = ( 1.9 \pm 0.6 _ { stat } \pm 0.4 _ { sys } ) \times 10 ^ { -13 } % cm ^ { -2 } s ^ { -1 } TeV ^ { -1 } corresponding to 0.5 \% of the Crab nebula differential flux and a spectral index \Gamma = 2.9 \pm 0.5 _ { stat } \pm 0.2 _ { sys } , 1ES 1312 - 423 is one of the faintest sources ever detected in the very high energy ( E > 100 { GeV } ) extragalactic sky .
A careful analysis using three and a half years of Fermi -LAT data allows the discovery at high energies ( E > 100 MeV ) of a hard spectrum ( \Gamma = 1.4 \pm 0.4 _ { stat } \pm 0.2 _ { sys } ) source coincident with 1ES 1312 - 423 .
Radio , optical , UV and X-ray observations complete the spectral energy distribution of this blazar , now covering 16 decades in energy .
The emission is successfully fitted with a synchrotron self Compton model for the non-thermal component , combined with a black-body spectrum for the optical emission from the host galaxy .