  Interaction of cosmological gamma ray burst radiation with the dense
interstellar medium of host galaxy is considered. Gas dynamical motion of
interstellar medium driven by gamma ray burst is investigated in 2D
approximation for different initial density distributions of host galaxy matter
and different total energy of gamma ray burst. The maximum velocity of motion
of interstellar medium is $1.8\cdot10^4$ km/s. Light curves of gamma ray burst
afterglow are calculated for set of non homogeneous density, distribution gamma
ray burst total energy, and different viewing angles. Spectra of gamma ray
burst afterglow are modeled taking into account conversion of hard photons
(soft X-ray, hard UV) to soft UV and optics photons.
