Distances
Such observations have allowed a distance to be estimated to the gamma ray bursts because spectral
lines and their Doppler shift have been observed in the transients after the burst. Assuming these
transients to be near the location of the gamma ray burst and the Doppler shifts to be Hubble
redshifts, these observations have almost conclusively shown that gamma ray bursts are at
cosmological distances and not in the halo of the local galaxy.