The DEEP2 Galaxy Redshift Survey and the role of environment in galaxy formation and evolution.

摘要

In this thesis, I first discuss the execution and principal data products of the DEEP2 Galaxy Redshift Survey, a spectroscopic redshift survey designed to study the galaxy population and large-scale structure of the Universe at z ∼ 1. In particular, I describe the spectroscopic observing operations and data reduction procedures developed and employed. In addition, DEEP2 is presented in comparison to past and present surveys of the local and distant galaxy populations, with an eye towards future studies at z ≳ 1. Finally, I detail the final DEEP2 redshift catalog and its public release.;Second, I test the applicability of various galaxy environment measures within deep redshift surveys, using mock galaxy catalogs to mimic representative photometric and spectroscopic redshift surveys at intermediate redshift ( z ∼ 1). From this analysis, I conclude that photometric redshifts lack the velocity precision required to cleanly discriminate the environments of galaxies, as even the smallest photometric-redshift errors achieved are much larger than galaxy correlation lengths ( 5 h -1 comoving Mpc versus > 15 h-1 comoving Mpc for sigmaz = 0.01). In addition, I study the impact of edges and holes in a survey field, redshift-space distortions, and target selection upon different environment estimators. For the DEEP2 survey, I conclude that among the environment measures tested the projected nth-nearest-neighbor distance measure provides the most accurate estimate of local galaxy density over a continuous and broad range of scales.;Using these techniques, derived from tests on mock galaxy catalogs, in conjunction with the DEEP2 data set, I then investigate the role of environment in the evolution of galaxy properties over the last 7--10 Gyr. I find that all major features of the relationship between rest-frame color and local galaxy density, as observed in the local Universe, were already in place at z ∼ 1. Furthermore, analysis of the evolution in the color-density relation at intermediate redshift shows that the build-up of red galaxies in dense regions is driven by group-like environments (i.e., not clusters), with typical ∼ L* galaxies beginning to quench and move onto the red sequence at z ∼ 2. While environment is critical to the build-up of the red sequence at z 1, inspection of the relationship between galaxy overdensity and star formation shows that environment does not play the dominant role in the decline of the cosmic star-formation rate space density from z ∼ 1 to z ∼ 0. In an attempt to build upon these results, I conclude by discussing future projects, designed with the goal of understanding the bimodal nature of the local galaxy population, including the formation of the massive early-type galaxy population.