A Galaxy Redshift Survey Near HST/COS AGN Sight Lines ("IGM-GAL")

Keeney et al. (2018) present a galaxy redshift survey around 47 sight lines to UV-bright AGN observed by the Cosmic Origins Spectrograph (COS) in order to establish the connection between galaxies and UV-detected absorption systems in the local Universe. The collection of UV-detected absorption systems was released previously as a MAST HLSP ('IGM'; Danforth et al. 2015). IGM-GAL releases the galaxy spectra obtained as a part of this survey for ~9,000 individual galaxies whose redshift we measured. For most sight lines this survey is >90% complete to ~0.1 L* galaxies within ~1 Mpc of the sight line. Repeat observations imply that this survey has a redshift accuracy of 60 km/s for emission-line galaxies, 100 km/s for absorption-line galaxies, and 80 km/s for composite galaxies that show both emission and absorption.