THE DEEP2 GALAXY REDSHIFT SURVEY: DESIGN, OBSERVATIONS, DATA REDUCTION, AND REDSHIFTS

Abstract

We describe the design and data sample from the DEEP2 Galaxy Redshift Survey,\nthe densest and largest precision-redshift survey of galaxies at z ~ 1\ncompleted to date. The survey has conducted a comprehensive census of massive\ngalaxies, their properties, environments, and large-scale structure down to\nabsolute magnitude M_B = -20 at z ~ 1 via ~90 nights of observation on the\nDEIMOS spectrograph at Keck Observatory. DEEP2 covers an area of 2.8 deg^2\ndivided into four separate fields, observed to a limiting apparent magnitude of\nR_AB=24.1. Objects with z < 0.7 are rejected based on BRI photometry in three\nof the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5\ntimes more efficiently than in a purely magnitude-limited sample. Approximately\nsixty percent of eligible targets are chosen for spectroscopy, yielding nearly\n53,000 spectra and more than 38,000 reliable redshift measurements. Most of the\ntargets which fail to yield secure redshifts are blue objects that lie beyond z\n~ 1.45. The DEIMOS 1200-line/mm grating used for the survey delivers high\nspectral resolution (R~6000), accurate and secure redshifts, and unique\ninternal kinematic information. Extensive ancillary data are available in the\nDEEP2 fields, particularly in the Extended Groth Strip, which has evolved into\none of the richest multiwavelength regions on the sky. DEEP2 surpasses other\ndeep precision-redshift surveys at z ~ 1 in terms of galaxy numbers, redshift\naccuracy, sample number density, and amount of spectral information. We also\nprovide an overview of the scientific highlights of the DEEP2 survey thus far.\nThis paper is intended as a handbook for users of the DEEP2 Data Release 4,\nwhich includes all DEEP2 spectra and redshifts, as well as for the\npublicly-available DEEP2 DEIMOS data reduction pipelines. [Abridged]\n