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The Northern Sky Optical Cluster Survey. II. An Objective Cluster Catalog for 5800 Square Degrees

Gal, R. R. and de Carvalho, R. R. and Lopes, P. A. A. and Djorgovski, S. G. and Brunner, R. J. and Mahabal, A. and Odewahn, S. C. (2003) The Northern Sky Optical Cluster Survey. II. An Objective Cluster Catalog for 5800 Square Degrees. Astronomical Journal, 125 (4). pp. 2064-2084. ISSN 0004-6256. doi:10.1086/368240.

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We present a new, objectively defined catalog of candidate galaxy clusters based on the galaxy catalogs from the digitized Second Palomar Observatory Sky Survey. This cluster catalog, derived from the best calibrated plates in the high-latitude (|b| > 30°) northern Galactic cap region, covers 5800 deg^2 and contains 8155 candidate clusters. A simple adaptive kernel density mapping technique, combined with the SExtractor object detection algorithm, is used to detect galaxy overdensities, which we identify as clusters. Simulations of the background galaxy distribution and clusters of varying richnesses and redshifts allow us to optimize detection parameters and measure the completeness and contamination rates for our catalog. Cluster richnesses and photometric redshifts are measured, using integrated colors and magnitudes for each cluster. An extensive spectroscopic survey is used to confirm the photometric results. This catalog, with well-characterized sample properties, provides a sound basis for future studies of cluster physics and large-scale structure.

Item Type:Article
Related URLs:
URLURL TypeDescription
de Carvalho, R. R.0000-0002-1283-3363
Djorgovski, S. G.0000-0002-0603-3087
Mahabal, A.0000-0003-2242-0244
Additional Information:© 2003 The American Astronomical Society. Received 2002 September 24; accepted 2002 December 26. We thank the Norris Foundation and other private donors for their generous support of the DPOSS project. R. R. G. was supported in part by an NSF Fellowship, NASA GSRP NGT 5-50215, a Kingsley Fellowship, as well as a KDI grant to A. Szalay. This work would have been impossible without the POSS-II photographic team and the STScI digitization team. We also thank the Palomar telescope allocation committee and directors for generous time allocations for the DPOSS calibration effort. The DPOSS survey would have been impossible without the hard work of the POSS-II observing staff and numerous undergraduates who assisted with the calibration. R. R. G. would like to thank Sandra Castro for assistance with the spectroscopy reductions, and R. d. C. thanks Hugo Capelato, Angela Iovino, and Gary Mamon for discussion on several issues in this project. This work was made possible in part through the NPACI sponsored Digital Sky project and a generous equipment grant from SUN Microsystems. Access to the POSS-II image data stored on the HPSS, located at the California Institute of Technology, was provided by the Center for Advanced Computing Research.
Funding AgencyGrant Number
Kenneth T. and Eileen L. Norris FoundationUNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
NASA Graduate Student Research FellowshipNGT 5-50215
Kingsley FellowshipUNSPECIFIED
Subject Keywords:catalogs — galaxies: clusters: general — large-scale structure of universe — surveys
Issue or Number:4
Record Number:CaltechAUTHORS:20190924-112423363
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Official Citation:R. R. Gal et al 2003 AJ 125 2064
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:98832
Deposited By: Tony Diaz
Deposited On:24 Sep 2019 18:43
Last Modified:16 Nov 2021 17:41

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