The Arizona CDFS Environment Survey (ACES): A Magellan/IMACS Spectroscopic Survey of the Chandra Deep Field-South

We present the Arizona CDFS Environment Survey (ACES), a recently completed spectroscopic redshift survey of the Chandra Deep Field-South (CDFS) conducted using the Inamori-Magellan Areal Camera and Spectrograph on the Magellan-Baade telescope. In total, the survey targeted 7277 unique sources down to a limiting magnitude of R_AB = 24.1, yielding 5080 secure redshifts across the ∼30 arcmin × 30 arcmin extended CDFS region. The ACES data set delivers a significant increase to both the spatial coverage and the sampling density of the spectroscopic observations in the field. Combined with previously published spectroscopic redshifts, ACES now creates a highly complete survey of the galaxy population at R < 23, enabling the local galaxy density (or environment) on relatively small scales (∼1 Mpc) to be measured at z < 1 in one of the most heavily studied and data-rich fields in the sky. Here, we describe the motivation, design and implementation of the survey and present a preliminary redshift and environment catalogue. In addition, we utilize the ACES spectroscopic redshift catalogue to assess the quality of photometric redshifts from both the COMBO-17 and Multiwavelength Survey by Yale-Chile imaging surveys of the CDFS. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.Hubble Fellow.Spitzer Fellow.