Galaxies and Intergalactic Matter at Redshift z ∼ 3: Overview

Abstract

We present the first results from a survey of the relative spatial distributions of galaxies, intergalactic neutral hydrogen, and intergalactic metals at high redshift. We obtained high-resolution spectra of eight bright quasars (QSOs) at 3.1 < z < 4.1 and spectroscopic redshifts for 431 Lyman break galaxies (LBGs) at slightly lower redshifts. Comparing the locations of galaxies to the absorption lines in the QSO spectra shows that the intergalactic medium contains less neutral hydrogen than the global average within r ≲ 0.5 h -1 comoving Mpc of LBGs and more than average at slightly larger distances 1 h -1 comoving Mpc ≲ r ≲ 5 h -1 comoving Mpc. The intergalactic medium within the largest overdensities at z ~ 3, which will presumably evolve into the intracluster medium by z ~ 0, is rich in neutral hydrogen and C IV. The lack of H I absorption at small distances from LBGs appears unlikely to be produced solely by the Lyman continuum radiation they emit; it may show that the galaxies' supernova-driven winds maintain their measured outflow velocities of ~600 km s -1 for a few hundred million years and drive away nearby intergalactic gas. We present correlation functions of galaxies with Lyα forest flux decrements, with C IV systems, and with other galaxies. We describe the association of galaxies with damped Lyα systems and with intergalactic He II opacity. A strong observed correlation of galaxies with intergalactic metals supports the idea that LBG winds have enriched their surroundings.