Pair Production Absorption Troughs in Gamma-Ray Burst Spectra: A Potential Distance Discriminator

摘要

In order to explain the emergence of a high-energy continuum in gamma-ray bursts detected by EGRET, relativistic bulk motion with large Lorentz factors has recently been inferred for these sources regardless of whether they are of Galactic or cosmological origin. This conclusion results from calculations of internal pair production opacities in bursts that usually assume an infinite power-law source spectrum for simplicity, an approximation that is quite adequate for some bursts detected by EGRET.