A Uniform Analysis of the Ly-alpha forest at z = 0 - 5: I. The sample and distribution of clouds at z > 1.7

Abstract

We present moderate resolution data for 39 QSOs at z $\approx$ 2 obtained at the Multiple Mirror Telescope. These data are combined with spectra of comparable resolution of 60 QSOs with redshifts greater than 1.7 found in the literature to investigate the distribution of Ly-alpha forest lines in redshift and equivalent width. We find a value for $γ$, the parameter describing the number distribution of Ly-alpha forest lines in redshift, of $1.88\pm0.22$ for lines stronger than a rest equivalent width of 0.32 $Å$, in good agreement with some previous studies. The Kolmogorov-Smirnov test was applied to the data and it is found that this single power law is a good fit over the relevant redshift ranges. Simulations of the Lyman alpha forest were performed to determine the completeness of the line lists and to test how well the analysis the underlying line statistics, given this level of completeness.