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The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts

Newman, Jeffrey A. and Kassin, Susan A. and Noeske, K. G. and Kirby, Evan N. and Lotz, Jennifer M. (2013) The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts. Astrophysical Journal Supplement Series, 208 (1). Art. No. 5. ISSN 0067-0049. doi:10.1088/0067-0049/208/1/5.

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We describe the design and data analysis of the DEEP2 Galaxy Redshift Survey, the densest and largest high-precision redshift survey of galaxies at z ~ 1 completed to date. The survey was designed to conduct a comprehensive census of massive galaxies, their properties, environments, and large-scale structure down to absolute magnitude M_B = −20 at z ~ 1 via ~90 nights of observation on the Keck telescope. The survey covers an area of 2.8 deg^2 divided into four separate fields observed to a limiting apparent magnitude of R_(AB) = 24.1. Objects with z ≾0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5 times more efficiently than in a purely magnitude-limited sample. Approximately 60% of eligible targets are chosen for spectroscopy, yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements. Most of the targets that fail to yield secure redshifts are blue objects that lie beyond z ~ 1.45, where the [O ii] 3727 Å doublet lies in the infrared. The DEIMOS 1200 line mm^(−1) grating used for the survey delivers high spectral resolution (R ~ 6000), accurate and secure redshifts, and unique internal kinematic information. Extensive ancillary data are available in the DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into one of the richest multiwavelength regions on the sky. This paper is intended as a handbook for users of the DEEP2 Data Release 4, which includes all DEEP2 spectra and redshifts, as well as for the DEEP2 DEIMOS data reduction pipelines. Extensive details are provided on object selection, mask design, biases in target selection and redshift measurements, the spec2d two-dimensional data-reduction pipeline, the spec1d automated redshift pipeline, and the zspec visual redshift verification process, along with examples of instrumental signatures or other artifacts that in some cases remain after data reduction. Redshift errors and catastrophic failure rates are assessed through more than 2000 objects with duplicate observations. Sky subtraction is essentially photon-limited even under bright OH sky lines; we describe the strategies that permitted this, based on high image stability, accurate wavelength solutions, and powerful B-spline modeling methods. We also investigate the impact of targets that appear to be single objects in ground-based targeting imaging but prove to be composite in Hubble Space Telescope data; they constitute several percent of targets at z ~ 1, approaching ~5%–10% at z > 1.5. Summary data are given that demonstrate the superiority of DEEP2 over other deep high-precision redshift surveys at z ~ 1 in terms of redshift accuracy, sample number density, and amount of spectral information. We also provide an overview of the scientific highlights of the DEEP2 survey thus far.

Item Type:Article
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URLURL TypeDescription Paper
Newman, Jeffrey A.0000-0001-8684-2222
Kirby, Evan N.0000-0001-6196-5162
Lotz, Jennifer M.0000-0003-3130-5643
Additional Information:© 2013 The American Astronomical Society. Received 2012 March 14; accepted 2013 May 31; published 2013 August 29. Thanks are due to the many institutions and individuals who have made the DEEP2 survey possible. First thanks go to the W. M. Keck Foundation, the University of California, and NASA for providing funds to construct and operate the Keck telescopes. Second, we wish to thank the technical teams in the UCO/Lick Shops and at Keck Observatory for their role in building and commissioning the DEIMOS spectrograph and for their superb support during many observing runs. Funds for the spectrograph were provided by instrumentation grant ARI 92-14621 from the National Science Foundation and instrument funds from the California Association for Research in Astronomy (Keck Observatory) and from the University of California/Lick Observatory. The DEIMOS data-reduction pipeline is based in part on code from the Princeton Sloan Digital Sky Survey spectrograph pipeline, and we thank Scott Burles and David Schlegel for their help in adapting this software for DEIMOS. Particularly vital components were the SDSS code developed for slitlet extractions, B-spline sky subtraction, and redshift determination. Patrik Jonsson’s study of fringing in the LRIS spectrograph led to the basic understanding of fringing needed to establish image stability specifications for DEIMOS. The ATV image display tool created by Aaron Barth, SPLOT created by David Schlegel, the IDL Astronomy User’s Library supported by the Goddard Space Flight Center, and the idlutils package were all instrumental in this work. The submit_prepare perl script by Marshall Perrin was of great assistance in the submission of this paper. We benefitted greatly from advice and input from Jeremy Mould, Charles Steidel, Mark Metzger, Richard Ellis, Chris Conselice, Harlan Epps, Edward Groth, Garth Illingworth, Richard Kron, Alex Szalay, Roc Cutri, Charles Beichman, Peter Eisenhardt, Giovanni Fazio, and Kevin Bundy in conceiving, designing, and executing the survey. We wish to thank the anonymous referee for their detailed reading and helpful comments on this paper, and for helping to raise awareness of our unconscious boreal-centrism. We also wish to thank the entire DEEP1 team for their pioneering efforts which helped greatly in designing DEEP2. The DEEP2 survey was initiated under the auspices of the NSF Center for Particle Astrophysics. Major grant support was provided by National Science Foundation grants AST 95-29098, 00-711098, 05-07483, and 08-08133 to UCSC, AST 00-71048, 05-07428, and 08-07630 to UCB, and 08-06732 to the University of Pittsburgh. Computing hardware used to analyze DEEP2 data was provided by Sun Microsystems. The HST ACS imaging mosaic in EGS was constructed by Anton Koekemoer and Jennifer Lotz and was funded by grant HST-AR-01947 from NASA. NASA imaging of the original Groth Strip was planned and executed by Ed Groth and Jason Rhodes with support from NAS5-1661 and NAG5-6279 to the WFPC1 IDT. Support for this work was provided by NASA through Hubble Fellowship grants 51256.01 and 51269.01 awarded to E.N.K. and M.C.C., respectively, by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS 5-26555. Sandra Faber thank CARA for a generous research grant and the Miller Institute at UC Berkeley for a Visiting Miller Professorship, during which much of this paper was written. Jeffrey Newman and Alison Coil acknowledge support from Hubble Fellowships during their DEEP2 work, and Michael Cooper acknowledges support from both Hubble and Spitzer Fellowships. Marc Davis acknowledges support from the entire DEEP2 team who filled in while he was recovering from a stroke. Finally, we recognize and acknowledge the highly significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community; it has been a privilege to be given the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
W. M. Keck FoundationUNSPECIFIED
University of CaliforniaUNSPECIFIED
NSFARI 92-14621
Lick ObservatoryUNSPECIFIED
NSFAST 95-29098
NSFAST 00-711098
NSFAST 05-07483
NSFAST 08-08133
NSFAST 00-71048
NSFAST 05-07428
NSFAST 08-07630
NSFAST 08-06732
NASA Hubble Fellowship51256.01
NASA Hubble Fellowship51269.01
NASANAS 5-26555
Miller Institute for Basic Research in ScienceUNSPECIFIED
NASA Spitzer FellowshipUNSPECIFIED
Subject Keywords:cosmology: observations; galaxies: distances and redshifts; galaxies: evolution; galaxies: fundamental parameters; galaxies: high-redshift; galaxies: statistics; large-scale structure of universe; methods: data analysis; surveys
Issue or Number:1
Record Number:CaltechAUTHORS:20131015-090200542
Persistent URL:
Official Citation:Jeffrey A. Newman et al. 2013 ApJS 208 5 doi:10.1088/0067-0049/208/1/5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41913
Deposited By: Tony Diaz
Deposited On:15 Oct 2013 16:46
Last Modified:10 Nov 2021 04:35

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