SDSS_DR8.SclGroup table

The SclGroup table links superclusters with individual galaxy groups. The table is useful for joining GalGroup and Supercluster tables.

Table structure

ColumnTypeUCDUnitDescription
groupidintmeta.id
meta.main
group/cluster id
dleveldecimal(3,1)stat.paramdensity level
sclidintmeta.idsupercluster id where the group belongs
adapttinyintmeta.codeadaptive flag

Sample queries

  1. Get all galaxy groups belonging to the supercluster Scl 27 at fixed density threshold D = 5.0. This query joins the GalGroup and SclGalaxy tables, assigns table aliases, and fetches all columns from the GalGroup table.
    SELECT gr.*
    FROM SDSS_DR8.GalGroup AS gr
    JOIN SDSS_DR8.SclGroup AS sclgr USING (groupid)
    WHERE sclgr.sclid=27 AND sclgr.dlevel=5.0
  2. Get all galaxy groups from superclusters found with the adaptive density threshold where the luminosity lum_tot_gal is larger than 300. This query joins the GalGroup, SclGroup and Supercluster tables, and fetches all columns from the GalGroup table together with the supercluster ID sclid and density level dlevel.
    SELECT gr.*, scl.sclid, scl.dlevel
    FROM SDSS_DR8.GalGroup AS gr
    JOIN SDSS_DR8.SclGroup AS sclgr USING (groupid)
    JOIN SDSS_DR8.Supercluster AS scl USING (sclid,dlevel)
    WHERE scl.lum_tot_gal > 300 AND scl.adapt=1