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SDSSWHLGC - Sloan Digital Sky Survey DR6 Galaxy Clusters Catalog

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Overview

Clusters of galaxies in most of the previous catalogs have redshifts z <= 0.3. Using the photometric redshifts of galaxies from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6), the authors identify 39,716 clusters in the redshift range 0.05 < z < 0.6 with more than eight luminous (M_r <= -21) member galaxies. Cluster redshifts are estimated accurately with an uncertainty of less than 0.022. The contamination rate of member galaxies is found to be roughly 20%, and the completeness of member galaxy detection reaches ~90%. Monte Carlo simulations show that the cluster detection rate is more than 90% for massive (M_200 > 2 x 10^14 M_sun, where M_200 is the total mass within the radius in which the mean mass density is 200 times the critical cosmic mass density) clusters of z <= 0.42. The false detection rate is ~5%. The authors obtain the richness, the summed luminosity, and the gross galaxy number within the determined radius for identified clusters. They are tightly related to the X-ray luminosity and temperature of the clusters. Cluster mass is related to the richness and summed luminosity with M_200 ~ R^(1.90+/-0.04)^ and M_200 ~ L_r^(1.64+/-0.03)^, respectively. In addition, 790 new candidate X-ray clusters are found by cross-identification of these clusters with the source list of the ROSAT X-ray All-Sky Survey.

Catalog Bibcode

2009ApJS..183..197W

References

Galaxy Clusters Identified from the SDSS DR6 and Their Properties
      Wen Z.L., Han J.L., Liu F.S.
     <Astrophys. J. Suppl. 183, 197 (2009)>
     =2009ApJS..183..197W

Provenance

This table was created by the HEASARC in August 2009 based on electronic versions of Tables 1 and 2 from the paper which were obtained from the Astrophysical Journal web site.

Parameters

Name
The J2000.0 position-based source designation of the cluster of galaxies using the 'WHL' prefix (for Wen Han, Liu), and the coordinates of the cluster center. Notice that the HEASARC found 15 pairs of cases with duplicate names (including one pair with identical photometric redshifts as well), and added 'A' and 'B' suffixes to differentiate these otherwise duplicate names:

  |Cluster Name         | Photometric Redshift

  |WHL J072815.2+350037A|  0.3494
  |WHL J072815.2+350037B|  0.3612
  |WHL J080822.1+293007A|  0.3946
  |WHL J080822.1+293007B|  0.3972
  |WHL J092124.0+273835A|  0.5222
  |WHL J092124.0+273835B|  0.6525
  |WHL J093139.6+202323A|  0.1735
  |WHL J093139.6+202323B|  0.1948
  |WHL J100200.2+082629A|  0.2173
  |WHL J100200.2+082629B|  0.2235
  |WHL J101448.3+104411A|  0.1996
  |WHL J101448.3+104411B|  0.2096
  |WHL J101854.3-021019A|  0.2064
  |WHL J101854.3-021019B|  0.2154
  |WHL J120252.8+380214A|  0.4578
  |WHL J120252.8+380214B|  0.4593
  |WHL J125811.4+492245A|  0.4708
  |WHL J125811.4+492245B|  0.5020
  |WHL J133426.4+372722A|  0.2890
  |WHL J133426.4+372722B|  0.3188
  |WHL J134327.5+400726A|  0.2318
  |WHL J134327.5+400726B|  0.2334
  |WHL J135520.1+490106A|  0.4961
  |WHL J135520.1+490106B|  0.4972
  |WHL J151602.8+653707A|  0.3165
  |WHL J151602.8+653707B|  0.3208
  |WHL J155040.2+092314A|  0.3633
  |WHL J155040.2+092314B|  0.3633
  |WHL J155846.7+413157A|  0.3776
  |WHL J155846.7+413157B|  0.3795
  

RA
The Right Ascension of the cluster center in the selected equinox. This was constructed by the HEASARC from the name, which contains the position in J2000.0 cordinates, with the RA given to a precision of 0.1 seconds of time.

Dec
The Declination of the cluster center in the selected equinox. This was constructed by the HEASARC from the name, which contains the position in J2000.0 cordinates, with the Dec given to a precision of 1 arcsecond.

LII
The Galactic Longitude of the cluster center.

BII
The Galactic Latitude of the cluster center.

RA_BCG
The Right Ascension of the brightest cluster galaxy (BCG) in the selected equinox. This was given in the reference paper table in J2000.0 coordinates and in degrees, to a precision of 10-5 degrees.

Dec_BCG
The Declination of the brightest cluster galaxy (BCG) in the selected equinox. This was given in the reference paper table in J2000.0 coordinates and in degrees, to a precision of 10-5 degrees.

Redshift
The photometric redshift of the cluster.

Spect_Redshift
The spectroscopic redshift of the brightest cluster galaxy.

Rmag_BCG
The r-band magnitude of the brightest cluster galaxy.

Num_Galaxies
The number of member galaxy candidates (N_gal) within 1 Mpc.

Cluster_Richness
The cluster richness R, defined by the number of real member galaxies in the region, but subtracting contamination from foreground and background galaxies. See Section 2.2 of the reference paper for more details.

Gross_Galaxy_Num
The gross galaxy number of the cluster. This is the number of luminous galaxies within the radius for member galaxy detection (galaxy_det_radius), after subtracting the background.

Galaxy_Det_Radius
The radius for member galaxy detection, in Mpc. For many clusters, the radius of 1 Mpc is not the boundary of the luminous cluster galaxies. The boundary can be recognized from the number counts within annuli. See Section 2.2 of the reference paper for more details.

Rband_Luminosity
The summed r-band luminosity of the cluster, L_r, in units of solar luminosities.

Overdensity_Level
The overdensity level of the cluster. This is defined as the difference between the actual number of galaxies with absolute r-band magnitude <= 21 within a radius of 0.5 Mpc and the average background number within the same radius and redshift range in multiples of the rms of the average background number. See Section 2.2 of the reference paper for more details

Other_Catalogs
Other catalogs containing the cluster:

  Abell:  Abell 1958, ApJS, 3, 211; Abell et al. 1989, ApJS, 70, 1;
  Zwcl:   Zwicky et al. 1968, Catalog of Galaxies and Clusters of galaxies;
  CE:     Goto et al. 2002, AJ, 123, 1807;
  NSC:    Gal et al. 2003, AJ, 125, 2064;
  NSCS:   Lopes et al. 2004, AJ, 128, 1017;
  maxBCG: Koester et al. 2007, ApJ, 660, 239;
  RXC:    Bohringer et al. 2000, ApJ, 129, 435; 2004, A&A, 425, 367.
  

Xray_Name
The designation of the ROSAT X-ray candidate counterpart source.

Projected_Offset
The projected separation between the X-ray source and the cluster BCG (brightest cluster galaxy), in Mpc.

RASS_Count_Rate
The ROSAT X-ray source count rate in the 0.1-2.4 keV energy band, in ct/s.


Contact Person

Questions regarding the SDSSWHLGC database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 12-Aug-2009