SDSS_DR8.Galaxy table

The Galaxy table is a subset SDSS DR8 Legacy Survey. 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). Additional table columns are described in Tempel et al. (2012).

Table structure

ColumnTypeUCDUnitDescription
galidintmeta.id
meta.main
our unique identification number for galaxies
groupidintmeta.id.parentthe group/cluster id
ngalintmeta.numberthe richness of the group the galaxy belongs to
zcmbdoublesrc.redshiftthe redshift, corrected to the CMB rest frame
distdoublepos.distanceMpc/hthe co-moving distance (calculated directly from redshift)
groupdistdoublepos.distanceMpc/hthe co-moving distance to the group/cluster centre, where the galaxy belongs to, calculated as an average over all galaxies, belonging to the group/cluster
raj2000doublepos.eq.radegright ascension
dej2000doublepos.eq.decdegdeclination
glondoublepos.galactic.londeggalactic longitude
glatdoublepos.galactic.latdeggalactic latitude
etadoubleposdegSDSS survey coordinate, eta
lamdoubleposdegSDSS survey coordinate, lambda
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
mag+5log10(h)the absolute magnitude of the galaxy in u filter, k+e-corrected
absmag_gfloatphot.mag
em.opt.B
mag+5log10(h)the absolute magnitude of the galaxy in g filter, k+e-corrected
absmag_rfloatphot.mag
em.opt.R
mag+5log10(h)the absolute magnitude of the galaxy in r filter, k+e-corrected
absmag_ifloatphot.mag
em.opt.I
mag+5log10(h)the absolute magnitude of the galaxy in i filter, k+e-corrected
absmag_zfloatphot.mag
em.opt.I
mag+5log10(h)the absolute magnitude of the galaxy in z filter, k+e-corrected
kcor_ufloatarith.factor
phot.mag
em.opt.U
magthe k-correction (u filter) by KCORRECT algorithm
kcor_gfloatarith.factor
phot.mag
em.opt.B
magthe k-correction (g filter) by KCORRECT algorithm
kcor_rfloatarith.factor
phot.mag
em.opt.R
magthe k-correction (r filter) by KCORRECT algorithm
kcor_ifloatarith.factor
phot.mag
em.opt.I
magthe k-correction (i filter) by KCORRECT algorithm
kcor_zfloatarith.factor
phot.mag
em.opt.I
magthe k-correction (z filter) by KCORRECT algorithm
lum_rfloatphys.luminosity
em.opt.R
10+10Lsun/h2the observed luminosity in the r-band
weightfloatstat.weightthe weight factor for the galaxy (weight times lum_r was used to calculate the luminosity density field)
rankintmeta.recordthe galaxy rank in its group, calculated based on the galaxy luminosity: for the most luminous galaxy, the rank is 1
den1floatsrc.densityThe normalised environmental density of the galaxy for the smoothing scale of 1 Mpc/h
den2floatsrc.densityThe normalised environmental density of the galaxy for the smoothing scale of 2 Mpc/h
den4floatsrc.densityThe normalised environmental density of the galaxy for the smoothing scale of 4 Mpc/h
den8floatsrc.densityThe normalised environmental density of the galaxy for the smoothing scale of 8 Mpc/h
den16floatsrc.densityThe normalised environmental density of the galaxy for the smoothing scale of 16 Mpc/h
dist_edgefloatpos.distanceMpc/hthe co-moving distance of the galaxy from the border of the survey mask
morftinyintmeta.code.classthe morphology of the galaxy (0- unclear, 1- spiral, 2- ellipt)
hc_efloatstat.probabilitythe Huertas-Company et al. (2011) mark of being an early type galaxy
objid_dr8bigintmeta.id.crossthe SDSS DR8 photometric object identification number
specobjid_dr8bigintmeta.id.crossthe SDSS DR8 spectroscopic object identification number
galid_dr7intmeta.id.crossan unique identification number to link with the entries in our previous DR7 group catalogue
zobsdoublesrc.redshiftthe observed redshift (without CMB correction)
dist_cordoublepos.distanceMpc/hthe co-moving distance of the galaxy where the finger-of-god effect is suppressed (as used in luminosity density field calculations)
flag_fctinyintmeta.codeif greater than zero, indicates that the galaxy has a missing (with unknown redshift) neighbour due to a fibre collision