SIMBAD references

We report the discovery of fast variability of γ-ray flares from blazar OJ 287. This blazar is known to be powered by a binary system of supermassive black holes. The observed variability time-scale T_var≲ 3-10 h is much shorter than the light-crossing time of the more massive (1.8 {x} 10¹⁰ M_☉) black hole and is comparable to the light-crossing time of the less massive (1.3 {x} 10⁸ M_☉) black hole. This indicates that γ-ray emission is produced by the relativistic jet ejected by the black hole of smaller mass. Detection of γ-rays with energies in excess of 10 GeV during the fast variable flares constrains the Doppler factor of the jet to be larger than 4. The possibility of studying the orbital modulation of emission from the relativistic jet makes OJ 287 a unique laboratory for the study of the mechanism(s) of formation of jets by black holes, and in particular the response of the jet parameters to changes in the parameters of the medium from which the black hole accretes and into which the jet expands.