Chandra COSMOS (C-COSMOS) Survey Optical/IR Counterparts Catalog

Chandra COSMOS (C-COSMOS) Survey Optical/IR Counterparts Catalog CCOSMOSOID ivo://nasa.heasarc/ccosmosoid NASA/GSFC HEASARC Civano et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8-Ms, Chandra program that has imaged the central 0.9 deg2 of the COSMOS field down to limiting depths of 1.9 x 10-16 erg/cm2/s in the soft (0.5-2 keV) band, 7.3 x 10-16 erg/cm2/s in the hard (2-10 keV) band, and 5.7 x 10-16 erg/cm2/s in the full (0.5-10 keV) band. In this Paper III of the series of papers on this survey, the authors report the i, K, and 3.6-um identifications of the 1761 X-ray point sources. They use the likelihood ratio technique to derive the association of optical/infrared counterparts for 97% of the X-ray sources. For most of the remaining 3%, the presence of multiple counterparts or the faintness of the possible counterpart prevented a unique association. For only 10 X-ray sources, they were not able to associate a counterpart, mostly due to the presence of a very bright field source close by. Only two sources are truly empty fields. The full catalog, including spectroscopic and photometric redshifts and classification described here in detail, is available herein. See also the related table <a href="ccosmoscat.html">CCOSMOSCAT</a> for the the surveyed X-ray point sources. This table was created by the HEASARC in December 2012, based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/201/30">CDS Catalog J/ApJS/201/30</a> file catalog.dat. This is a service provided by NASA HEASARC . 2012ApJS..201...30C https://heasarc.gsfc.nasa.gov/W3Browse/all/ccosmosoid.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ccosmosoid& GET text/xml 180 99999 true 150.33663 1.601612 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ccosmosoid GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ccosmosoid&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public ccosmosoid Chandra COSMOS (C-COSMOS) Survey Optical/IR Counterparts Catalog source_number Sequential Identification Number for Each Source in Catalog meta.id;src int nullable name IAU-Style Source Designation (CXOC JHHMMSS.s+DDMMSS) as in Elvis et al. 2009 meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable flux X-Ray 0.5-10 keV Flux erg/s/cm^2 phot.flux;em.X-ray double nullable imag i(AB) Band Magnitude (at 3" Aperture) from Capak et al. 2007, Cat. II/284 mag phot.mag;em.opt.I double nullable imag_error i(AB) Band Magnitude Error mag stat.error;phot.mag;em.opt.I double nullable kmag K(AB)-Band Magnitude (at 3" Aperture) from McCracken et al. 2010ApJ...708..202M mag phot.mag;em.IR.K double nullable kmag_error K(AB)-Band Magnitude Error mag stat.error;phot.mag;em.IR.K double nullable broad_type Spectroscopic Classification (1=BLAGN, 2=not-BLAGN, 0=Star) src.class short nullable redshift Spectroscopic Redshift from the Optical, K, or 3.6-Micron Catalogs src.redshift double nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable star_flag Flag Indicates a Star: 1=Spectroscopic Confirmed Star, 10=Photometric Star meta.code short nullable hb_flux X-Ray 2-10 keV Flux erg/s/cm^2 phot.flux;em.X-ray.medium double nullable kmag_ctrpart_ra Right Ascension of the K-Band Counterpart degree pos.eq.ra double nullable ctrpart_ra Right Ascension of the Optical/IR Counterpart degree pos.eq.ra double nullable xmmc_name XMM-Newton Identifier from Brusa et al. 2010 meta.id char nullable irac_ctrpart_dec Declination of the IRAC 3.6-Micron Counterpart degree pos.eq.ra double nullable redshift_flag Flag Indicates Spectroscopic Redshift Quality meta.code;src.redshift short nullable flux_3p6_um Spitzer/IRAC 3.6-Micron Flux from Sanders et al. 2007ApJS..172...86S microJy phot.flux.density;em.IR.3-4um double nullable phot_redshift Photometric Redshift from Salvato et al. 2011ApJ...742...61S src.redshift.phot double nullable lii Galactic Longitude degree pos.galactic.lon double nullable off_nuclear_flag Boolean Flag Indicates Isolated Off-Nuclear Sources meta.code short nullable kmag_ctrpart_dec Declination of the K-Band Counterpart degree pos.eq.dec double nullable phot_sed_type Redshift Classification from SED Fitting (1=Unobscured, 2=Obscured, 3=Galaxy) meta.code;src.class short nullable ctrpart_dec Declination of the Optical/IR Counterpart degree pos.eq.dec double nullable ci_ctrpart_ra Right Ascension of the Optical Counterpart degree pos.eq.ra double nullable ilbert_source_number Optical Identifier from the Revised Catalog (Ilbert et al. 2009ApJ...690.1236I) meta.id.cross int nullable final_id_flag Final Identification Flag: 1=Secure, 10=Ambiguous, 100=Subthreshold meta.code short nullable ci_ctrpart_dec Declination of the Optical Counterpart degree pos.eq.dec double nullable flux_3p6_um_error 3.6-Micron Flux Error microJy double nullable bii Galactic Latitude degree pos.galactic.lat double nullable sb_flux X-Ray 0.5-2 keV Flux erg/s/cm^2 phot.flux;em.X-ray.soft double nullable ref_redshift Reference Code for Spectroscopic Redshift meta.ref;src.redshift short nullable capak_source_number Optical Identifier from Capak et al. Catalog (Cat. II/284) meta.id.cross int nullable irac_ctrpart_ra Right Ascension of the IRAC 3.6-Micron Counterpart degree pos.eq.ra double nullable