Candels: The Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey

Abstract

The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) is designed to document the first third of galactic evolution, over the approximate redshift (z) range 8-1.5. It will image >250,000 distant galaxies using three separate cameras on the Hubble Space Telescope, from the mid-ultraviolet to the near-infrared, and will find and measure Type Ia supernovae at z > 1.5 to test their accuracy as standardizable candles for cosmology. Five premier multi-wavelength sky regions are selected, each with extensive ancillary data. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to a stellar mass of 10 9 M to z ≈ 2, reaching the knee of the ultraviolet luminosity function of galaxies to z ≈ 8. The survey covers approximately 800 arcmin 2 and is divided into two parts. The CANDELS/Deep survey (5σ point-source limit H = 27.7 mag) covers ∼125 arcmin 2 within Great Observatories Origins Deep Survey (GOODS)-N and GOODS-S. The CANDELS/Wide survey includes GOODS and three additional fields (Extended Groth Strip, COSMOS, and Ultra-deep Survey) and covers the full area to a 5σ pointsource limit of H 27.0 mag. Together with the Hubble Ultra Deep Fields, the strategy creates a three-tiered "wedding-cake" approach that has proven efficient for extragalactic surveys. Data from the survey are nonproprietary and are useful for a wide variety of science investigations. In this paper, we describe the basic motivations for the survey, the CANDELS team science goals and the resulting observational requirements, the field selection and geometry, and the observing design. The Hubble data processing and products are described in a companion paper.

The Impact of JWST Broadband Filter Choice on Photometric Redshift Estimation

“…In order to obtain multiwavelength photometry for these galaxies, we cross-matched this sample with the public Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS; Grogin et al 2011;Koekemoer et al 2011) catalog for the Great Observatory Origins Deep Survey South field (GOODS-S) obtained by Guo et al (2013). This catalog contains photometry in 17 broadbands, from 0.37 through 8.0 μm, obtained with ground-and space-based telescopes, including HST and Spitzer (Ashby et al 2015).…”

The Spitzer Extragalactic Representative Volume Survey (SERVS): Survey Definition and Goals*

“…For consistency, the depth shown is the 5σ limiting flux for point sources, excluding confusion noise ( as described in Section 4.2), calculated from the Spitzer performance estimation tool (http://ssc.spitzer.caltech.edu/ warmmission/propkit/pet/senspet /index.html) in each case. The surveys are (from left to right): GOODS, the Spitzer follow-up to the CANDELS HST survey (Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey, Grogin et al 2011), the Spitzer Extragalactic Deep Survey (SEDS, Program identifier-hereafter PID-60022, 61040, 61041, 61042, 61043, P.I. G. Fazio), the Spitzer IRAC/MUSYC Public Legacy in E-CDFS (SIMPLE) survey (Spitzer, PID 20708), the Spitzer Ultra Deep Survey (SpUDS, PID 40021, P.I.…”

“…Progress in extragalactic astronomy has been greatly enhanced by deep surveys such as the Great Observatories Origins Deep Survey (GOODS; Dickinson et al 2003), the Cosmic Evolution Survey (COSMOS; Sanders et al 2007), the Galaxy Mass Assembly Ultradeep Spectroscopic Survey (GMASS; Cimatti et al 2008), and the HST Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS; Grogin et al 2011;Koekemoer et al 2011), which have allowed us to study the evolution of galaxies from the earliest cosmic epochs. However, a limitation of such surveys is the relatively small volumes probed, even at high redshifts: for example, Ilbert et al (2006) find noticeable field-to-field variations in redshift distributions in the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS 43 ) in fields of 0:7-0:9 deg 2 .…”

Using AGN Variability Surveys to explore the AGN-Galaxy Connection

“…Grogin et al 2005). The SEDS fields are also covered by CANDELS (Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey; Grogin et al 2011), which has obtained deep, highresolution HST imaging at 1 to 1.6 microns with HST WFC3 in portions of these fields. Recent CANDELS results have found that, for X-ray selected AGN, the fraction of irregular and disturbed host galaxies is no greater than that of a control sample (Kocevski et al 2012).…”