With the release of the first year Fermi catalogue, the number of blazars detected above 100 MeV lying at high redshift has been largely increased. There are 28 blazars at z>2 in the clean sample. All of them are Flat Spectrum Radio Quasars (FSRQs). We study and model their overall spectral energy distribution in order to find the physical parameters of the jet emitting region, and for all of them we estimate their black hole masses and accretion rates. We then compare the jet with the accretion disk properties, setting these sources in the broader context of all the other bright gamma-ray or hard X-ray blazars. We confirm that the jet power correlates with the accretion luminosity. We find that the high energy emission peak shifts to smaller frequencies as the observed luminosity increases, according to the blazar sequence, making the hard X-ray band the most suitable for searching the most luminous and distant blazars.
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