The C4 clustering algorithm [electronic resource] : Clusters of galaxies in the Sloan Digital Sky Survey
- Published:
- Washington, D.C. : United States. Dept. of Energy, 2005.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Physical Description:
- 32 pages : digital, PDF file
- Additional Creators:
- Fermi National Accelerator Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
Access Online
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Summary:
- We present the ''C4 Cluster Catalog'', a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers ≈2600 square degrees of sky and ranges in redshift from z = 0.02 to z = 0.17. The mean cluster membership is 36 galaxies (with redshifts) brighter than r = 17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L{sub r}), velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multi-color mock SDSS galaxy catalogs, empirically constructed from the ΛCDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is ≃90% complete and 95% pure above M₂₀₀ = 1 x 10¹⁴ h⁻¹M{sub {circle_dot}} and within 0.03 ≤ z ≤ 0.12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray identified clusters and 90% of Abell clusters within 0.03 ≤ z ≤ 0.12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L{sub r} of a cluster is a more robust estimator of the halo mass (M₂₀₀) than the galaxy line-of-sight velocity dispersion or the richness of the cluster. However, if we exclude clusters embedded in complex large-scale environments, we find that the velocity dispersion of the remaining clusters is as good an estimator of M₂₀₀ as L{sub r}. The final C4 catalog will contain ≃ 2500 clusters using the full SDSS data set and will represent one of the largest and most homogeneous samples of local clusters.
- Report Numbers:
- E 1.99:fermilab-pub-05-064-a
fermilab-pub-05-064-a - Subject(s):
- Other Subject(s):
- Note:
- Published through SciTech Connect.
03/01/2005.
"fermilab-pub-05-064-a"
"arXiv eprint number astro-ph/0503713"
FT
McKay, Timothy; Annis, James; Bahcall, Neta; Bernardi, Mariangela; Sheth, Ravi; Schneider, Donald; Voges, Wolfgang; Miller, Christopher J.; Nichol, Robert; Wechsler, Risa H.; Evrard, August; Lamb, Donald; Connolly, Andrew; Reichart, Dan; Boehringer, Hans; Goto, Tomo; Kniazev, Alexie; Postman, Marc. - Funding Information:
- AC02-76CH03000
View MARC record | catkey: 13823220