Chandra Legacy Survey (CLS) Catalog

Chandra Legacy Survey (CLS) Catalog CLSCAT ivo://nasa.heasarc/clscat NASA/GSFC HEASARC Civano et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The COSMOS-Legacy survey is a 4.6-Ms Chandra program that has imaged 2.2 deg2 of the COSMOS field with an effective exposure of ~160 ks over the central 1.5 deg2 and of ~80 ks in the remaining area. The survey is the combination of 56 new observations obtained as an X-ray Visionary Project with the previous C-COSMOS survey. In the reference paper, the authors describe the reduction and analysis of the new observations and the properties of 2273 point sources detected above a spurious probability of 2 x 10-5. The authors also present the updated properties of the C-COSMOS sources detected in the new data. The whole survey includes 4,016 point sources (3,814, 2,920 and 2,440 in the full, soft, and hard band). The limiting depths are 2.2 x 10-16, 1.5 x 10-15, and 8.9 x 10-16 erg/cm2/s in the 0.5-2, 2-10, and 0.5-10 keV bands, respectively. The observed fraction of obscured active galactic nuclei with a column density > 1022 cm-2 from the hardness ratio (HR) is ~ 50+17_-16_%. Given the large sample, the authors compute source number counts in the hard and soft bands, significantly reducing the uncertainties of 5% - 10%. For the first time, they compute number counts for obscured (HR > -0.2) and unobscured (HR < -0.2) sources and find significant differences between the two populations in the soft band. Due to the unprecedented large exposure, the COSMOS-Legacy area is three times larger than surveys at similar depths and its depth is three times fainter than surveys covering similar areas. The area-flux region occupied by COSMOS-Legacy is likely to remain unsurpassed for years to come. The half-a-field shift tiling strategy was designed to uniformly cover the COSMOS Hubble area in depth and point-spread function (PSF) size by combining the old C-COSMOS (Elvis et al., 2009, ApJS, 184, 158) observations with the new Chandra ones (see Figure 1 in the reference paper). The main properties of the new ACIS-I Chandra COSMOS-Legacy observations are summarized in Table 1 therein. The observations took place in four blocks: 2012 November to 2013 January; 2013 March to July; 2013 October to 2014 January; and 2014 March. The mean net effective exposure time per field was 48.8 ks after all the cleaning and reduction operations. This table was created by the HEASARC in July 2016 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/819/62">CDS Catalog J/ApJ/819/62</a>, file table5.dat. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018. This is a service provided by NASA HEASARC . 2016ApJ...819...62C https://heasarc.gsfc.nasa.gov/W3Browse/all/clscat.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=clscat& GET text/xml 180 99999 true 150.132264 1.418729 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=clscat GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_clscat&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public clscat Chandra Legacy Survey (CLS) Catalog source_id Chandra Source Designation meta.id;src char nullable name Source Designation 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 error_radius X-Ray Positional Error arcsec stat.error;pos double nullable fb_count_rate_limit Limit Flag for 0.5-7keV Count Rate meta.code;phot.count;em.X-ray char nullable fb_count_rate The 0.5-7keV Count Rate ct/s phot.count;em.X-ray double nullable fb_count_rate_error The 0.5-7keV Count Rate Uncertainty ct/s stat.error;phot.count;em.X-ray double nullable fb_flux_limit Limit Flag for 0.5-10keV Flux meta.code;phot.flux;em.X-ray char nullable fb_flux The 0.5-10keV Flux erg/s/cm^2 phot.flux;em.X-ray double nullable fb_flux_error The 0.5-10keV Flux Uncertainty erg/s/cm^2 stat.error;phot.flux;em.X-ray double nullable sb_exposure The 0.5-2keV Exposure Time s time.duration;obs.exposure;em.X-ray.soft double nullable sb_counts_error The 0.5-2keV Aperture Photometry Counts Uncertainty ct stat.error;phot;em.X-ray.soft double nullable sb_flux_limit Limit Flag for 0.5-2keV Flux meta.code;phot.flux;em.X-ray.soft char nullable sb_counts The 0.5-2keV Aperture Photometry Counts ct phot;em.X-ray.soft double nullable hb_flux_limit Limit Flag for 2-10keV Flux meta.code;phot.flux;em.X-ray.medium char nullable sb_flux_error The 0.5-2keV Flux Uncertainty erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft double nullable fb_counts_error The 0.5-7keV Aperture Photometry Counts Uncertainty ct stat.error;phot;em.X-ray double nullable hb_detect_likelihood Maximum Likelihood Detection Value in 2-7keV Band stat.likelihood;phot.count;em.X-ray.medium double nullable hb_counts The 2-7keV Aperture Photometry Counts ct phot;em.X-ray.medium double nullable hb_count_rate The 2-7keV Count Rate ct/s phot.count;em.X-ray.medium double nullable fb_snr The 0.5-7keV Signal-to-Noise Ratio stat.snr;em.X-ray double nullable hardness_ratio Hardness Ratio, (H-S)/(H+S) phot.flux;arith.ratio;em.X-ray double nullable hb_exposure The 2-7keV Exposure Time s time.duration;obs.exposure;em.X-ray.medium double nullable hardness_ratio_min Hardness Ratio 90% Lower Limit phot.flux;arith.ratio;em.X-ray;stat.min double nullable fb_counts The 0.5-7keV Aperture Photometry Counts ct phot;em.X-ray double nullable hb_count_rate_error The 2-7keV Count Rate Uncertainty ct/s stat.error;phot.count;em.X-ray.medium double nullable sb_detect_likelihood Maximum Likelihood Detection Value in 0.5-2keV Band stat.likelihood;phot.count;em.X-ray.soft double nullable sb_flux The 0.5-2keV Flux erg/s/cm^2 phot.flux;em.X-ray.soft double nullable hb_flux The 2-10keV Flux erg/s/cm^2 phot.flux;em.X-ray.medium double nullable sb_count_rate_limit Limit Flag for 0.5-2 keV Count Rate meta.code;phot.count;em.X-ray.soft char nullable hb_count_rate_limit Limit Flag for 2-7keV Count Rate meta.code;phot.count;em.X-ray.medium char nullable bii Galactic Latitude degree pos.galactic.lat double nullable fb_exposure The 0.5-7keV Exposure Time s time.duration;obs.exposure;em.X-ray double nullable hb_flux_error The 2-10keV Flux Uncertainty erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable hardness_ratio_max Hardness Ratio 90% Upper Limit phot.flux;arith.ratio;em.X-ray;stat.max double nullable hb_counts_error The 2-7keV Aperture Photometry Counts Uncertainty ct stat.error;phot;em.X-ray.medium double nullable sb_count_rate The 0.5-2 keV Count Rate ct/s phot.count;em.X-ray.soft double nullable lii Galactic Longitude degree pos.galactic.lon double nullable hb_snr The 2-7keV Signal-to-Noise Ratio stat.snr;em.X-ray.medium double nullable sb_count_rate_error The 0.5-2 keV Count Rate Uncertainty ct/s stat.error;phot.count;em.X-ray.soft double nullable fb_detect_likelihood Maximum Likelihood Detection Value in 0.5-7keV Band stat.likelihood;phot.count;em.X-ray double nullable sb_snr The 0.5-2keV Signal-to-Noise Ratio stat.snr;em.X-ray.soft 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