SOFT-X-RAY FLASHES OF GAMMA-RAY BURSTS AS TRACERS OF THE DISTANCE OF THE BURSTERS

Following a recent suggestion in the literature (Paczynski 1991; Schae fer 1993), we investigate the potential of the soft X-ray hashes, whic h are observed to accompany gamma-ray bursts (GRBs), as a tool to cons train the distance scale of the bursters. If the bursters are located in a Galactic corona or at cosmological distances, then the bursts mus t cross the interstellar medium of the whole Galaxy on their way to th e observer. Based on a model of the Galactic dust and gas distribution from Chi and Wolfendale (1991) we demonstrate how in this case at ene rgies around 1 keV scattering by the dust and absorption by the gas wo uld influence the angular distribution of the observed X-ray flashes d ependent on their Galactic latitude. We finally discuss promises and l imitations of the observations of X-ray flashes as well as the search for dust-scattered transient X-ray halos of GRBs.