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The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups

Gerke, Brian F. and Newman, Jeffrey A. and Davis, Marc and Coil, Alison L. and Cooper, Michael C. and Dutton, Aaron A. and Faber, S. M. and Guhathakurta, Puragra and Konidaris, Nicholas and Koo, David C. and Lin, Lihwai and Noeske, Kai and Phillips, Andrew C. and Rosario, David J. and Weiner, Benjamin J. and Willmer, Christopher N. A. and Yan, Renbin (2012) The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups. Astrophysical Journal, 751 (1). Art. No. 50. ISSN 0004-637X.

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We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 < z < 1.5 and 1295 groups at z > 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above ~300 km s^(–1) to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for cosmological tests.

Item Type:Article
Related URLs:
URLURL TypeDescription
Newman, Jeffrey A.0000-0001-8684-2222
Cooper, Michael C.0000-0003-1371-6019
Faber, S. M.0000-0003-4996-214X
Guhathakurta, Puragra0000-0001-8867-4234
Konidaris, Nicholas0000-0003-1905-2815
Koo, David C.0000-0003-3385-6799
Lin, Lihwai0000-0001-7218-7407
Additional Information:© 2012 American Astronomical Society. Received 2011 June 29; accepted 2011 November 29; published 2012 May 4. We thank C. Marinoni for making the VDM group-finding algorithm available for our use. This work was supported in part by the NSF grantsAST-0507428, AST-0507483, AST-0071048, AST-0071198, AST-0808133, and AST-0806732. B.F.G. was supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. M.C.C. received support from NASA through the Hubble Fellowship grant HF-51269.01-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under the contract NAS 5-26555; and from the Southern California Center for Galaxy Evolution, a multi-campus research program funded by the University of California Office of Research. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The DEIMOS spectrograph was funded by a grant from CARA (Keck Observatory), an NSF Facilities and Infrastructure grant (AST92-2540), the Center for Particle Astrophysics, and by gifts from Sun Microsystems and the Quantum Corporation. The DEEP2 Redshift Survey has been made possible through the dedicated efforts of the DEIMOS staff at UC Santa Cruz who built the instrument and the Keck Observatory staff who have supported it on the telescope. Finally, the authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC02-76SF00515
NASA Hubble FellowshipHF-51269.01-A
Space Telescope Science InstituteUNSPECIFIED
Southern California Center for Galaxy EvolutionUNSPECIFIED
NASANAS 5-26555
Subject Keywords:galaxies: clusters: general; galaxies: high-redshift
Issue or Number:1
Record Number:CaltechAUTHORS:20120601-115611529
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Official Citation:The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups Brian F. Gerke et al. 2012 ApJ 751 50
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31776
Deposited By: Jason Perez
Deposited On:01 Jun 2012 21:49
Last Modified:09 Mar 2020 13:19

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