高能天体物理研究组知识库

The broad-line region (BLR) of flat-spectrum radio quasars (FSRQs) could have a "flat" geometrical structure to allow GeV gamma-ray photons to escape, to produce the observed gamma-ray flares with short timescales. In this paper, we collect the quasisimultaneous spectral energy distributions (SEDs) of the FSRQ 3C 454.3 obtained by the multi-wavelength campaigns spanning from 2007 July to 2011 January, and use a model with a "flat" structure BLR, an accretion disc and a dust torus to explain the SEDs of gamma-ray outbursts. We obtain the following results: (i) the jet is almost in equipartition between magnetic and particle energy densities during the outbursts; (ii) when the emitting region is located inside the cavity of the BLR, the covering factor f(BLR) of the BLR is very small-as the emitting region goes into the BLR structure, fBLR increases; (iii) the aperture angle a describing the BLR structure is about 45 degrees; (iv) the central black hole mass is about 5 x 10(8) M-circle dot rather than 4.4 x 109 M-circle dot .