Distribution functions of intergalactic clouds

Abstract

Width spectrum data derived from high-redshift QSO Ly-alpha absorption lines are used to study the statistical properties of intergalactic clouds. Several theoretical distribution functions for size and density are derived and tested against observational data for two types of line broadening: thermal and cosmological. Good agreement was found between the theoretical distribution functions and the observational data when the clouds were thermally broadened, and when distribution functions for both cloud size and width have a nonzero width. Attempts to fit the data with a single radius or density distribution function were unsuccessful.