We use high-quality, medium-resolution Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) observations of 82 UV-bright active galactic nuclei (AGNs) at redshifts z_AGN_<0.85 to construct the largest survey of the low-redshift intergalactic medium (IGM) to date: 5138 individual extragalactic absorption lines in HI and 25 different metal-ion species grouped into 2611 distinct redshift systems at z_abs_N)/dz=C_14_(N/10^14^/cm2)^-({beta}-1)^, with C_14_=25+/-1 and {beta}=1.65+/-0.02. This distribution is seen to evolve both in amplitude, C_14_{propto}(1+z)^2.3+/-0.1^, and slope {beta}(z)=1.75-0.31 z for z~1000km/s. Splitting the sample into strong and weak absorbers, we see that most of the clustering occurs in strong, N_HI_>~10^13.5^/cm2, metal-bearing IGM systems.

Cone search capability for table J/ApJ/817/111/table1 (HST/COS sight lines)