Dahai Yan, Houdun Zeng, Li Zhang
We study the locations of emission regions through modelling the
quasi-simultaneous multi-frequency spectral energy distributions of 21 {\it
Fermi} flat spectrum radio quasars (FSRQs) in the frame of a multi-component
one-zone leptonic model. In our calculations, we take the detailed broad line
region (BLR) structure into account and discuss the effect of the uncertainty
of the BLR structure on constraining the location of the emission regions for
each FSQR, meanwhile we also include both the internal and external
absorptions. Our results indicate that (1) the contribution of external
Compton-BLR component is important to $\gamma$-ray emission, and the energy
density of external target photon fields depends on the location of the
emission region, which can be derived through reproducing the observed
$\gamma$-ray emission, and (2) the emission regions of FSRQs with relative low
accretion disk luminosity lie in the region of $7.9\times10^{16}$\ --\
$1.3\times10^{18}$\ cm (300 -- 4300 Schwarzschild radii) from central black
hole, and for FSRQs with high accretion disk luminosity, the emission regions
locate in the larger region of $2.6\times10^{17}$\ --\ $4.2\times10^{18}$\ cm
(300 -- 5600 Schwarzschild radii).
View original:
http://arxiv.org/abs/1202.1602
No comments:
Post a Comment