We develop a general expression for the gamma-gamma absorption coefficient
for gamma-rays propagating in an arbitrary direction at an arbitrary point in
space above an X-ray emitting accretion disk. The X-ray intensity is assumed to
vary as a power law in energy and radius between the outer disk radius and the
inner radius, which is the radius of marginal stability for a Schwarzschild
black hole. We use our result for the absorption coefficient to calculate the
gamma-gamma optical depth for gamma-rays created at an arbitrary height and
propagating at an arbitrary angle relative to the disk axis. As an application,
we use our formalism to compute the minimum distance between the central black
hole and the site of production of the gamma-rays detected by EGRET during the
June 1991 flare of 3C 279. Our results indicate that the ``focusing'' of the
gamma-rays along the disk axis due to pair production is strong enough to
explain the observed degree of alignment in blazar sources. If the gamma-rays
are produced isotropically in gamma-ray blazars, then these objects should
appear as bright MeV sources when viewed along off-axis lines of sight.Comment: 23 pages, tex, figures available on request to [email protected]
