Absorption of 10 Gev--1 Tev Gamma Rays from 3C 279
  In this paper, we revisit gamma-ray--emitting region for 10 GeV--1 TeV gamma
rays from 3C 279 through studying the photon-photon absorption optical depth
due to the diffuse radiation of the broad-line region (BLR) and the
extragalactic background light (EBL). Based on the power-law spectrum detected
by MAGIC, the preabsorbed spectra are inferred by correcting the photon-photon
absorption on the diffuse photons of the BLR (internal absorption) and the EBL
(external absorption). Position of gamma-ray emitting region $R_{\rm{\gamma}}$
determines the relative contributions of this two diffuse radiation to the
total absorption. Our results indicate that $R_{\rm{\gamma}}$ may be within the
BLR shell for 3C 279, likely closer to the inner radius, which is consistent
with our previous results. This is neither consistent with the suggestions of
B\"ottcher et al. (2008b), that VHE gamma-ray emission is produced far outside
the BLR, nor with the assumptions of Tavecchio & Mazin (2008), that VHE
gamma-ray--emitting region is inside the BLR cavity. $R_{\rm{\gamma}}$ is a key
physical quantity that could set some constraints on emission mechanisms that
produce the VHE gamma rays from 3C 279. Observations of $\it Fermi$-LAT, MAGIC,
HESS, and VERITAS in the near future could give more constraints on the
position of gamma-ray emitting region relative to the BLR.
