The distribution of Lyman-alpha absorption lines in the spectra of six QSOs - Evidence for an intergalactic origin

Abstract

The large Lyman-alpha samples in five QSOs with zem between 2.2 and 3.3 are used to test whether the absorbing gas is cosmologically distributed or ejected from the QSOs. It is shown that there is no significant variation in line density with redshift, nor in the rest equivalent width spectrum among the QSOs. In addition, the mean number density of lines in each object is found to be the same, that is, 60 lines per delta z=1 with W greater than or equal to 0.32 A.