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:
- Spatial search on all images and small catalogs, using Atlas
- Advanced search on only the larger catalogs, using Gator
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 |
| Id | int | number | Catalog ID number per tile |
| tile | int | number | Image tile which contains this object |
| ra | double | deg | Right Ascension (J2000) |
| dec | double | deg | Declination (J2000) |
| zp_best | double | redshift |
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 | int | number |
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_gal | double | redshift | photo-z using the galaxy templates (every source has a redshift) |
| zl68_gal | double | redshift | lower limit, 68% confidence level |
| zu68_gal | double | redshift | upper limit, 68% confidence level |
| zl99_gal | double | redshift | lower limit, 99% confidence level |
| zu99_gal | double | redshift | upper limit, 99% confidence level |
| chi_gal | double | number | reduced chi2 (-99 if less than 3 filters) |
| mod_gal | int | number | best fit template (1->8 Ell-S0, 9->15 Sa-Sc, 16->19 Sd-Sdm from Polletta et al., >=20 from BC03). |
| ebv | double | number | additional extinction E(B-V) (Prevot et al. for templates <=24, Calzetti et al for template>24) |
| zp_sec | double | redshift | second photo-z solution |
| chi_sec | double | number | reduced chi2 for the second photo-z solution |
| mod_sec | int | number | template for the second photo-z solution |
| ebv_sec | double | number | additional extinction for the second photo-z solution |
| mod_star | int | number | model for the star library |
| chi_star | double | number | reduced chi2 |
| Umag | double | mag | CFHT u* aperture magnitude (3" aperture) |
| Bmag | double | mag | Subaru B aperture magnitude (3" aperture) |
| Vmag | double | mag | Subaru V aperture magnitude (3" aperture) |
| Gmag | double | mag | Subaru g+ aperture magnitude (3" aperture) |
| Rmag | double | mag | Subaru r+ aperture magnitude (3" aperture) |
| Imag | double | mag | Subaru i+ aperture magnitude (3" aperture) |
| Zmag | double | mag | Subaru z+ aperture magnitude (3" aperture) |
| ICmag | double | mag | CFHT i' aperture magnitude (3" aperture) |
| Jmag | double | mag | UKIRT J aperture magnitude (3" aperture) |
| Kmag | double | mag | CFHT K aperture magnitude (3" aperture) |
| eU | double | mag | CFHT u* error on the magnitude |
| eB | double | mag | Subaru B error on the magnitude |
| eV | double | mag | Subaru V error on the magnitude |
| eG | double | mag | Subaru g+ error on the magnitude |
| eR | double | mag | Subaru r+ error on the magnitude |
| eI | double | mag | Subaru i+ error on the magnitude |
| eZ | double | mag | Subaru z+ error on the magnitude |
| eIC | double | mag | CFHT i' error on the magnitude |
| eJ | double | mag | UKIRT J error on the magnitude |
| eK | double | mag | CFHT K error on the magnitude |
| flagB | int | number | mask in the B band, 0 good |
| flagV | int | number | mask in the V band, 0 good |
| flagi | int | number | mask in the I band, 0 good |
| flagz | int | number | mask in the Z band, 0 good |
| flagD | int | number | mask for the deep area, 0 good |
| NbFilt | int | number | Number of filters used in the photo-z fitting |
| I_auto | double | mag | Auto magnitude in the i band |
| auto_offset | double | mag | Offset to transform aperture magnitude into auto |
| auto_flag | int | number | Quality flag in the offset |
| MV | double | mag | absolute magnitude in the V(Subaru) band |