COSMOS Photometric Redshift Catalog (mag limit 25) Definitions

COSMOS Overview

The COSMOS Archive serves data taken for the Cosmic Evolution Survey (COSMOS) project. COSMOS is an astronomical survey designed to probe the formation and evolution of galaxies as a function of cosmic time (redshift) and large scale structural environment. The survey covers a 2 square degree equatorial field with imaging by most of the major space-based telescopes (Hubble, Spitzer, GALEX, XMM, Chandra) and a number of large ground based telescopes (Subaru, VLA, ESO-VLT, UKIRT, NOAO, CFHT, and others).

IRSA serves the COSMOS archive using the following search methods:

COSMOS Photometric Redshift Catalog, version 1.5, mag limig 25, Column Definitions

Gator serves the COSMOS October 2008 Photometric Redshift Catalog (55 columns [50 delivered + 5 IRSA-created], 385,065 data rows). The column descriptions can be found below. Please also see the photz catalog README file for more information about the catalog itself.

name intype units description
IdintnumberCatalog ID number per tile
tileintnumberImage tile which contains this object
radoubledegRight Ascension (J2000)
decdoubledegDeclination (J2000)
zp_best = zgal  if galaxy  (column 7)
zp_best = 0     if star
zp_best = 9.99  if Xray (Use the photo-z values from Salvato et al. 2008, released separately)
zp_best = 99.0  if IA>25.5 (faint sources with a lower photo-z accuracy, needs to be handle with extreme care)
zp_best = -99   if in a masked area
type = 0   if galaxy
type = 1   if star
type = 2   if Xray source
type = 3   if IA>25.5 (faint sources with a lower photo-z accuracy, needs to be handle with extreme care)
type = -99 if masked area
zp_galdoubleredshiftphoto-z using the galaxy templates (every source has a redshift)
zl68_galdoubleredshiftlower limit, 68% confidence level
zu68_galdoubleredshiftupper limit, 68% confidence level
zl99_galdoubleredshiftlower limit, 99% confidence level
zu99_galdoubleredshiftupper limit, 99% confidence level
chi_galdoublenumberreduced chi2 (-99 if less than 3 filters)
mod_galintnumberbest fit template
(1->8 Ell-S0, 9->15 Sa-Sc, 16->19 Sd-Sdm from Polletta et al., >=20 from BC03).
ebvdoublenumberadditional extinction E(B-V)
(Prevot et al. for templates <=24, Calzetti et al for template>24)
zp_secdoubleredshiftsecond photo-z solution
chi_secdoublenumberreduced chi2 for the second photo-z solution
mod_secintnumbertemplate for the second photo-z solution
ebv_secdoublenumberadditional extinction for the second photo-z solution
mod_starintnumbermodel for the star library
chi_stardoublenumberreduced chi2
UmagdoublemagCFHT u* aperture magnitude (3" aperture)
BmagdoublemagSubaru B aperture magnitude (3" aperture)
VmagdoublemagSubaru V aperture magnitude (3" aperture)
GmagdoublemagSubaru g+ aperture magnitude (3" aperture)
RmagdoublemagSubaru r+ aperture magnitude (3" aperture)
ImagdoublemagSubaru i+ aperture magnitude (3" aperture)
ZmagdoublemagSubaru z+ aperture magnitude (3" aperture)
ICmagdoublemagCFHT i' aperture magnitude (3" aperture)
JmagdoublemagUKIRT J aperture magnitude (3" aperture)
KmagdoublemagCFHT K aperture magnitude (3" aperture)
eUdoublemagCFHT u* error on the magnitude
eBdoublemagSubaru B error on the magnitude
eVdoublemagSubaru V error on the magnitude
eGdoublemagSubaru g+ error on the magnitude
eRdoublemagSubaru r+ error on the magnitude
eIdoublemagSubaru i+ error on the magnitude
eZdoublemagSubaru z+ error on the magnitude
eICdoublemagCFHT i' error on the magnitude
eJdoublemagUKIRT J error on the magnitude
eKdoublemagCFHT K error on the magnitude
flagBintnumbermask in the B band, 0 good
flagVintnumbermask in the V band, 0 good
flagiintnumbermask in the I band, 0 good
flagzintnumbermask in the Z band, 0 good
flagDintnumbermask for the deep area, 0 good
NbFiltintnumberNumber of filters used in the photo-z fitting
I_autodoublemagAuto magnitude in the i band
auto_offsetdoublemagOffset to transform aperture magnitude into auto
auto_flagintnumberQuality flag in the offset
MVdoublemagabsolute magnitude in the V(Subaru) band