SDSS_DR12.Galaxy table

The Galaxy table is based on the SDSS DR12. The table contains data on galaxies from the main contiguous area of the SDSS (7966 sq deg) with the redshift limit of z=0.2 and r-magnitude limit of 17.77. The basic galaxy parameters are taken from SDSS Catalog Archive Server (CAS).

Table structure

ColumnTypeUCDUnitDescription
galidintmeta.id
meta.main
our unique identification number for galaxies
specobjidbigintmeta.id.crossSDSS spectroscopic object identification number
objidbigintmeta.id.crossSDSS photometric object identification number
groupidintmeta.id.parentgroup/cluster id in the present database
ngalintmeta.numberrichness (number of members) of the group/cluster the galaxy belongs to
rankintmeta.recordluminosity rank of the galaxy within its group; rank 1 indicates the most luminous galaxy
groupdistdoublepos.distanceMpccomoving distance to the group/cluster centre, where the galaxy belongs to, calculated as an average over all galaxies within the group/cluster
zobsdoublesrc.redshiftobserved redshift (without the CMB correction)
zcmbdoublesrc.redshiftredshift, corrected to the CMB rest frame
zerrdoublestat.error
src.redshift
uncertainty of the redshift
distdoublepos.distanceMpccomoving distance (calculated directly from the CMB-corrected redshift)
dist_cordoublepos.distanceMpccomoving distance of the galaxy after suppressing of the Finger-of-God effect
raj2000doublepos.eq.radegright ascension
dej2000doublepos.eq.decdegdeclination
glondoublepos.galactic.londeggalactic longitude
glatdoublepos.galactic.latdeggalactic latitude
sglondoublepos.supergalactic.londegsupergalactic longitude
sglatdoublepos.supergalactic.latdegsupergalactic latitude
lamdoubleposdegSDSS survey coordinate, lambda
etadoubleposdegSDSS survey coordinate, eta
crd_xdoublepos.cartesian.xCartesian coordinate along the x-axis defined by eta and lambda
crd_ydoublepos.cartesian.yCartesian coordinate along the y-axis defined by eta and lambda
crd_zdoublepos.cartesian.zCartesian coordinate along the z-axis defined by eta and lambda
mag_ufloatphot.mag
em.opt.U
magGalactic-extinction-corrected Petrosian magnitude in u filter
mag_gfloatphot.mag
em.opt.B
magGalactic-extinction-corrected Petrosian magnitude in g filter
mag_rfloatphot.mag
em.opt.R
magGalactic-extinction-corrected Petrosian magnitude in r filter
mag_ifloatphot.mag
em.opt.I
magGalactic-extinction-corrected Petrosian magnitude in i filter
mag_zfloatphot.mag
em.opt.I
magGalactic-extinction-corrected Petrosian magnitude in z filter
absmag_ufloatphot.mag
em.opt.U
magabsolute magnitude of the galaxy in u filter, k+e-corrected
absmag_gfloatphot.mag
em.opt.B
magabsolute magnitude of the galaxy in g filter, k+e-corrected
absmag_rfloatphot.mag
em.opt.R
magabsolute magnitude of the galaxy in r filter, k+e-corrected
absmag_ifloatphot.mag
em.opt.I
magabsolute magnitude of the galaxy in i filter, k+e-corrected
absmag_zfloatphot.mag
em.opt.I
magabsolute magnitude of the galaxy in z filter, k+e-corrected
kecor_ufloatarith.factor
phot.mag
em.opt.U
magk+e-correction (u filter)
kecor_gfloatarith.factor
phot.mag
em.opt.B
magk+e-correction (g filter)
kecor_rfloatarith.factor
phot.mag
em.opt.R
magk+e-correction (r filter)
kecor_ifloatarith.factor
phot.mag
em.opt.I
magk+e-correction (i filter)
kecor_zfloatarith.factor
phot.mag
em.opt.I
magk+e-correction (z filter)
ext_ufloatphys.absorption.gal
em.opt.U
magGalactic extinction (u filter)
ext_gfloatphys.absorption.gal
em.opt.B
magGalactic extinction (g filter)
ext_rfloatphys.absorption.gal
em.opt.R
magGalactic extinction (r filter)
ext_ifloatphys.absorption.gal
em.opt.I
magGalactic extinction (i filter)
ext_zfloatphys.absorption.gal
em.opt.I
magGalactic extinction (z filter)
lum_rfloatphys.luminosity
em.opt.R
10+10Lsunobserved luminosity in the r-band, where Lsun = 4.64 mag (Blanton & Roweis 2007)
weightfloatstat.weightweight factor for the galaxy (w times lum_r was used to calculate the luminosity density field)
hc_efloatstat.probabilityprobability of being an early-type galaxy (from Huertas-Company et al. 2011)
hc_s0floatstat.probabilityprobability of being an S0 galaxy
hc_sabfloatstat.probabilityprobability of being an Sab galaxy
hc_scdfloatstat.probabilityprobability of being an Scd galaxy
dist_edgefloatpos.distanceMpccomoving distance of the galaxy from the border of the survey mask
den1_5floatsrc.densitynormalized environmental density of the galaxy for the smoothing scale of 1.5 Mpc
den3floatsrc.densitynormalized environmental density of the galaxy for the smoothing scale of 3 Mpc
den6floatsrc.densitynormalized environmental density of the galaxy for the smoothing scale of 6 Mpc
den10floatsrc.densitynormalized environmental density of the galaxy for the smoothing scale of 10 Mpc

Sample queries

  1. Select all columns for a specific galaxy, based on the ID number galid:
    SELECT * FROM SDSS_DR12.Galaxy WHERE galid=1
  2. Select all galaxies that belong to the galaxy group with the ID groupid of 1:
    SELECT * FROM SDSS_DR12.Galaxy WHERE groupid=1
  3. Get the number of galaxies for each luminosity rank in the group the galaxy belongs to:
    SELECT rank,COUNT(*) FROM SDSS_DR12.Galaxy GROUP BY rank