Access to Astronomical Catalogues

J/MNRAS/413/3059    4098 galaxy clusters in SDSS Stripe 82   (Geach+, 2011)
4098 galaxy clusters to z∼0.6 in the Sloan Digital Sky Survey equatorial
Stripe 82.
    Geach J.E., Murphy D.N.A., Bower R.G.
   <Mon. Not. R. Astron. Soc., 413, 3059-3067 (2011)>
   =2011MNRAS.413.3059G
ADC_Keywords: Clusters, galaxy ; Redshifts ; QSOs

Keywords: catalogues - galaxies: clusters: general -
          large-scale structure of Universe

Abstract:
    We present a catalogue of 4098 photometrically selected galaxy
    clusters with a median redshift <z≥0.32 in the 270deg2 "Stripe 82"
    region of the Sloan Digital Sky Survey (SDSS), covering the celestial
    equator in the Southern Galactic Cap (-50°<RA<59°,
    |DE|≤1.25). Owing to the multi-epoch SDSS coverage of this region,
    the ugriz photometry is ∼2mag deeper than single scans within the
    main SDSS footprint. We exploit this to detect clusters of galaxies
    using an algorithm that searches for statistically significant
    overdensities of galaxies in a Voronoi tessellation of the projected
    sky.

Description:
    We have chosen to distribute the full catalogue in Hierarchical Data
    Format (HDF, version 5). This format provides a natural way for us to
    release both the 'top level' cluster properties (coordinate,
    redshift, etc.) and a wide range of other information, including
    various richness classifications, and information for each of the
    constituent galaxies. However, for simple access, we also provide a
    "supplementary QSO sightline catalogue".

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
clusters.dat     186     4098   Stripe 82 cluster catalogue, top level
qsos.dat          88    18295   Supplementary QSO sightline catalogue
clusters.hdf5    512   529861   Full catalogue in Hierarchical Data Format
                              (HDF, version 5)


Byte-by-byte Description of file: clusters.dat

   Bytes Format Units   Label     Explanations

   1-  4  I4    ---     Cluster   Cluster sequential number
   6- 23 E18.15 deg     RAdeg     Cluster right ascension (J2000)
  25- 43 E19.15 deg     DEdeg     Declination (J2000)
  45- 62 E18.15 deg     RA1deg    BCG right ascension (J2000) (1)
  64- 82 E19.15 deg     DE1deg    BCG declination (J2000) (1)
  84- 86  I3    ---     Ngal      Number of galaxies assigned to cluster
  88-105 E18.15 ---     z         Cluster redshift
 107-126  A20   ---     n_z       Code describing composite average of galaxy
                                   redshifts (unexplained)
 128-145 E18.15 rad     r80       Angular radius containing 80% of the members
 147-164 E18.15 ---     C         Concentration index (C=r80/r20)
     166  I1    ---     R         [1/4]?=- Richness class
 168-186 E19.15 ---     Agc       ?=- Richness estimator (amplitude of the
                                  angular correlation function)

Note (1): BCG = Brightest Cluster Galaxy



Byte-by-byte Description of file: qsos.dat

   Bytes Format Units   Label     Explanations

   1-  6  I6    ---     QSO       QSO identification number
   8- 17  F10.8 deg     Sep       Separation from cluster center, in degrees
  19- 28  F10.8 Mpc     R         Separation from cluster center, in Mpc
  30- 34  F5.3  ---     zQSO      QSO redshift
  36- 43  F8.4  deg     RAdeg     QSO right ascension (J2000)
  45- 52  F8.5  deg     DEdeg     QSO declination (J2000)
  54- 57  F4.1  mag     Vmag      QSO V magnitude
  59- 66  F8.6  ---     zCl       Cluster redshift
  68- 79  F12.8 deg     RAcdeg    Cluster right ascension degrees (J2000)
  81- 88  F8.5  deg     DEcdeg    Cluster declination (J2000)


History:
    Copied at http://www.physics.mcgill.ca/~jimgeach/stripe82
(End)                                      Patricia Vannier [CDS]    15-Dec-2011