PROBING THE INTERGALACTIC MEDIUM-GALAXY CONNECTION TOWARD PKS 0405-123. III. THE GALAXY SURVEY AND CORRELATIONS WITH O VI ABSORBERS

摘要

We present a galaxy survey of the field surrounding PKS 0405 — 123 performed with the WFCCD spectrometer at Las Campanas Observatory. The survey is comprised of two data sets: (1) a greater than 95% complete survey to R = 20 mag of the field centered on PKS 0405-123 with 10′ radius (L ≈ 0.1L_* and radius of 1 Mpc at z = 0.1); and (2) a set of four discontiguous (i.e., nonoverlapping), flanking fields covering ≈ 1 deg~2 area with completeness ≈ 90% to R = 19.5 mag. With these data sets, one can examine the local and large-scale galactic environment of the absorption systems identified toward PKS 0405 — 123. In this paper, we focus on the O VI systems analyzed in Paper I. The results suggest that this gas arises in a diverse set of galactic environments including the halos of individual galaxies, galaxy groups, filamentary-like structures, and also regions devoid of luminous galaxies. In this small sample, there are no obvious trends between galactic environment and the physical properties of the gas. Furthermore, we find similar results for a set of absorption systems with comparable N_(H I) but no detectable metal lines. The observations indicate that metals are distributed throughout a wide range of environments in the local universe. Future papers in this series will address the distribution of galactic environments associated with metal-line systems and the Lyα forest based on data for over 10 additional fields. All of the data presented in this paper are made public at a dedicated web site.