The C4 clustering algorithm: Clusters of galaxies in the Sloan digital sky survey

Christopher J. Miller, Robert C. Nichol, Daniel Reichart, Risa H. Wechsler, August E. Evrard, James Annis, Timothy A. McKay, Neta A. Bahcall, Mariangela Bernardi, Hans Boehringer, Andrew J. Connolly, Tomotsugu Goto, Alexie Kniazev, Donald Lamb, Marc Postman, Donald P. Schneider, Ravi K. Sheth, Wolfgang Voges

Research output: Contribution to journalReview article

221 Citations (Scopus)

Abstract

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 deg 2 of sky and ranges in redshift from z = 0.02 to 0.17. The mean cluster membership is 36 galaxies (with measured 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 measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L r), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the ACDM 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 M 200 = 1 × 10 14 h -1 M⊙ 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 r of a cluster is a more robust estimator of the halo mass (M 200) 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 M 200 as L 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.

Original languageEnglish (US)
Pages (from-to)968-1001
Number of pages34
JournalAstronomical Journal
Volume130
Issue number3
DOIs
StatePublished - Sep 1 2005

Fingerprint

galaxies
catalogs
estimators
sky
simulation
completeness
substructures
line of sight
halos
dark matter
purity
apertures
projection
luminosity
color

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Miller, C. J., Nichol, R. C., Reichart, D., Wechsler, R. H., Evrard, A. E., Annis, J., ... Voges, W. (2005). The C4 clustering algorithm: Clusters of galaxies in the Sloan digital sky survey. Astronomical Journal, 130(3), 968-1001. https://doi.org/10.1086/431357
Miller, Christopher J. ; Nichol, Robert C. ; Reichart, Daniel ; Wechsler, Risa H. ; Evrard, August E. ; Annis, James ; McKay, Timothy A. ; Bahcall, Neta A. ; Bernardi, Mariangela ; Boehringer, Hans ; Connolly, Andrew J. ; Goto, Tomotsugu ; Kniazev, Alexie ; Lamb, Donald ; Postman, Marc ; Schneider, Donald P. ; Sheth, Ravi K. ; Voges, Wolfgang. / The C4 clustering algorithm : Clusters of galaxies in the Sloan digital sky survey. In: Astronomical Journal. 2005 ; Vol. 130, No. 3. pp. 968-1001.
@article{7f7ffd357d4f45ee917a444a2bd2f80f,
title = "The C4 clustering algorithm: Clusters of galaxies in the Sloan digital sky survey",
abstract = "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 deg 2 of sky and ranges in redshift from z = 0.02 to 0.17. The mean cluster membership is 36 galaxies (with measured 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 measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L r), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the ACDM 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 M 200 = 1 × 10 14 h -1 M⊙ 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 r of a cluster is a more robust estimator of the halo mass (M 200) 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 M 200 as L 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.",
author = "Miller, {Christopher J.} and Nichol, {Robert C.} and Daniel Reichart and Wechsler, {Risa H.} and Evrard, {August E.} and James Annis and McKay, {Timothy A.} and Bahcall, {Neta A.} and Mariangela Bernardi and Hans Boehringer and Connolly, {Andrew J.} and Tomotsugu Goto and Alexie Kniazev and Donald Lamb and Marc Postman and Schneider, {Donald P.} and Sheth, {Ravi K.} and Wolfgang Voges",
year = "2005",
month = "9",
day = "1",
doi = "10.1086/431357",
language = "English (US)",
volume = "130",
pages = "968--1001",
journal = "Astronomical Journal",
issn = "0004-6256",
publisher = "IOP Publishing Ltd.",
number = "3",

}

Miller, CJ, Nichol, RC, Reichart, D, Wechsler, RH, Evrard, AE, Annis, J, McKay, TA, Bahcall, NA, Bernardi, M, Boehringer, H, Connolly, AJ, Goto, T, Kniazev, A, Lamb, D, Postman, M, Schneider, DP, Sheth, RK & Voges, W 2005, 'The C4 clustering algorithm: Clusters of galaxies in the Sloan digital sky survey', Astronomical Journal, vol. 130, no. 3, pp. 968-1001. https://doi.org/10.1086/431357

The C4 clustering algorithm : Clusters of galaxies in the Sloan digital sky survey. / Miller, Christopher J.; Nichol, Robert C.; Reichart, Daniel; Wechsler, Risa H.; Evrard, August E.; Annis, James; McKay, Timothy A.; Bahcall, Neta A.; Bernardi, Mariangela; Boehringer, Hans; Connolly, Andrew J.; Goto, Tomotsugu; Kniazev, Alexie; Lamb, Donald; Postman, Marc; Schneider, Donald P.; Sheth, Ravi K.; Voges, Wolfgang.

In: Astronomical Journal, Vol. 130, No. 3, 01.09.2005, p. 968-1001.

Research output: Contribution to journalReview article

TY - JOUR

T1 - The C4 clustering algorithm

T2 - Clusters of galaxies in the Sloan digital sky survey

AU - Miller, Christopher J.

AU - Nichol, Robert C.

AU - Reichart, Daniel

AU - Wechsler, Risa H.

AU - Evrard, August E.

AU - Annis, James

AU - McKay, Timothy A.

AU - Bahcall, Neta A.

AU - Bernardi, Mariangela

AU - Boehringer, Hans

AU - Connolly, Andrew J.

AU - Goto, Tomotsugu

AU - Kniazev, Alexie

AU - Lamb, Donald

AU - Postman, Marc

AU - Schneider, Donald P.

AU - Sheth, Ravi K.

AU - Voges, Wolfgang

PY - 2005/9/1

Y1 - 2005/9/1

N2 - 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 deg 2 of sky and ranges in redshift from z = 0.02 to 0.17. The mean cluster membership is 36 galaxies (with measured 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 measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L r), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the ACDM 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 M 200 = 1 × 10 14 h -1 M⊙ 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 r of a cluster is a more robust estimator of the halo mass (M 200) 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 M 200 as L 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.

AB - 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 deg 2 of sky and ranges in redshift from z = 0.02 to 0.17. The mean cluster membership is 36 galaxies (with measured 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 measured redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L r), and velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multicolor mock SDSS galaxy catalogs, empirically constructed from the ACDM 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 M 200 = 1 × 10 14 h -1 M⊙ 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 r of a cluster is a more robust estimator of the halo mass (M 200) 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 M 200 as L 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.

UR - http://www.scopus.com/inward/record.url?scp=25844455623&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=25844455623&partnerID=8YFLogxK

U2 - 10.1086/431357

DO - 10.1086/431357

M3 - Review article

AN - SCOPUS:25844455623

VL - 130

SP - 968

EP - 1001

JO - Astronomical Journal

JF - Astronomical Journal

SN - 0004-6256

IS - 3

ER -

Miller CJ, Nichol RC, Reichart D, Wechsler RH, Evrard AE, Annis J et al. The C4 clustering algorithm: Clusters of galaxies in the Sloan digital sky survey. Astronomical Journal. 2005 Sep 1;130(3):968-1001. https://doi.org/10.1086/431357