Galaxies and intergalactic matter at redshift z∼3:: Overview

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 less than or similar to 0.5 h(-1) comoving Mpc of LBGs and more than average at slightly larger distances 1 h(-1) comoving Mpc less than or similar to r less than or similar to 5 h(-1) comoving Mpc. The intergalactic medium within the largest overdensities at z similar to 3, which will presumably evolve into the intracluster medium by z similar to 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 similar to600 km s(-1) for a few hundred million years and drive away nearby intergalactic gas. We present correlation functions of galaxies with Lyalpha forest flux decrements, with C IV systems, and with other galaxies. We describe the association of galaxies with damped Lyalpha 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.