Groth-Westphal Strip Chandra X-Ray Point Source Catalog GWSSTRPCXO ivo://nasa.heasarc/gwsstrpcxo NASA/GSFC HEASARC Nandra et al., Georgakakis et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the optical and X-ray spectral properties of the sources detected in a 200-ks Chandra observation of part of the Groth-Westphal Strip (GWS) region, using the ACIS-I instrument. The authors present a relatively simple method for the detection of X-ray point sources and the calculation of limiting sensitivities, which they argue is at least as sensitive and more self-consistent than previous methods presented in the literature. A total of 158 distinct X-ray sources are included in this point-source catalogue in the ACIS-I area with a threshold Poisson detection probability of 4 x 10<sup>-6</sup>. The number counts show a relative dearth of X-ray sources in this region. A wealth of optical photometric and spectroscopic data are available in this field providing optical identifications and redshift determinations for the X-ray population. The optical photometry and spectroscopy used here are primarily from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) survey with additional redshifts obtained from the literature. These are complemented with the deeper (r ~ 26 mag) multiwaveband data (ugriz) from the Canada-France-Hawaii Telescope Legacy Survey to estimate photometric redshifts and to optically identify sources fainter than the DEEP2 magnitude limit (R<sub>AB</sub> ~ 24.5 mag). The authors focus their study on the 2 - 10 keV selected sample comprising 97 sources to the flux limit ~8 x 10<sup>-16</sup> erg/s/cm<sup>2</sup>, this being the most complete in terms of optical identification rate (86 per cent) and redshift determination fraction (63 per cent; both spectroscopic and photometric). Chandra observed the GWS, which is part of the Extended Groth Strip (EGS) region, on three separate occasions between 2002 August 11 and 22, using ACIS-I as the prime instrument. The S2 and S3 chips of the ACIS-S array were also operating during the observation, but as these are far off-axis their data are not considered further. The sequence number identifying the observations was 900144 and the three observation ID numbers (3305 on 2002-08-11, 4357 on 2002-08-12, and 4365 on 2002-08-21). This table was created by the HEASARC in July 2007 based on the merger of <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/356/568">CDS Catalog J/MNRAS/356/568</a> file table3.dat and <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/371/221">CDS Catalog J/MNRAS/371/221</a> file table2.dat. This is a service provided by NASA HEASARC . 2006MNRAS.371..221G https://heasarc.gsfc.nasa.gov/W3Browse/all/gwsstrpcxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=gwsstrpcxo& GET text/xml 180 99999 true 214.252875 52.32182778 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=gwsstrpcxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_gwsstrpcxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Optical X-ray public gwsstrpcxo Groth-Westphal Strip Chandra X-Ray Point Source Catalog name Catalog Source Designation (CXOGWS JHHMMSS.s+DDMMSS) 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 counts Full-Band (0.5-7keV) Counts ct phot.count;em.X-ray double nullable counts_pos_err Upper Error on Full-Band Counts ct stat.error;phot.count;em.X-ray double nullable counts_neg_err Lower Error on Full-Band Counts ct stat.error;phot.count;em.X-ray double nullable rmag_limit Limit Flag for R Magnitude meta.code;phot.mag;em.opt.R char nullable rmag R Magnitude in AB System mag phot.mag;em.opt.R double nullable redshift Spectroscopic Redshift src.redshift double nullable phot_redshift Photometric Redshift src.redshift double nullable lx Unobscured 0.5-10keV X-Ray Luminosity (erg/s) erg/s phys.luminosity;em.X-ray double nullable source_flags Flags Indicate Bands of Low Probability Detection meta.code char nullable hb_flux_limit Limit Flag for 2-10keV Flux meta.code;phot.flux;em.X-ray.medium char nullable uhb_flux Flux at 5-10keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.medium double nullable sb_counts_neg_err Lower Error on Soft-Band Counts ct stat.error;phot.count;em.X-ray.soft double nullable uhb_counts_pos_err Upper Error on Ultra-Hard-Band Counts ct stat.error;phot.count;em.X-ray.medium double nullable phot_redshift_pos_err Upper Error on Photometric Redshift stat.error;src.redshift double nullable hb_counts Hard-Band (2-7keV) Counts ct phot.count;em.X-ray.medium double nullable sb_flux Flux at 0.5-2keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.soft double nullable uhb_flux_pos_err Upper RMS Uncertainty on 5-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable nh_neg_err Lower Error on NH (cm^-2) H-atoms/cm^2 stat.error;phys.columnDensity double nullable sb_counts_limit Limit Flag for Soft-Band Counts meta.code;phot.count;em.X-ray.soft char nullable off_axis Off-Axis Angle (arcmin) arcmin instr.offset double nullable phot_redshift_neg_err Lower Error on Photometric Redshift stat.error;src.redshift double nullable hb_flux Flux at 2-10keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray.medium double nullable flux Flux at 0.5-10keV (erg/s/cm^2) erg/s/cm^2 phot.flux;em.X-ray double nullable uhb_counts_limit Limit Flag for Ultra-Hard-Band Counts meta.code;phot.count;em.X-ray.medium char nullable flux_neg_err Lower Error on 0.5-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray double nullable prob_random_limit Limit Flag for Spurious Alignment Probability meta.code;stat.probability char nullable sb_counts Soft-Band, 0.5-2keV) Counts ct phot.count;em.X-ray.soft double nullable uhb_flux_limit Limit Flag for 5-10keV Flux meta.code;phot.flux;em.X-ray.medium char nullable hb_counts_pos_err Upper Error on Hard-Band Counts ct stat.error;phot.count;em.X-ray.medium double nullable hb_flux_pos_err Upper Error on 2-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable source_type Optical Spectroscopic Classification src.class char nullable hb_counts_neg_err Lower Error on Hard-Band Counts ct stat.error;phot.count;em.X-ray.medium double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id char nullable uhb_counts_neg_err Lower Error on Ultra-Hard-Band Counts ct stat.error;phot.count;em.X-ray.medium double nullable hb_counts_limit Limit Flag for Hard-Band Counts meta.code;phot.count;em.X-ray.medium char nullable sb_flux_pos_err Upper Error on 0.5-2keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft double nullable log_pmin Logarithm of Lowest False Detection Probability Found for the Four Bands stat.probability double nullable ref_redshift Reference Code for Source of Spectroscopic Redshift meta.ref;src.redshift short nullable nh_pos_err Upper Error on NH (cm^-2) H-atoms/cm^2 stat.error;phys.columnDensity double nullable prob_random Probability That the Optical Counterpart Is Spurious Alignment percent stat.probability double nullable sb_flux_neg_err Lower Error on 0.5-2keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft double nullable bii Galactic Latitude degree pos.galactic.lat double nullable sb_counts_pos_err Upper Error on Soft-Band Counts ct stat.error;phot.count;em.X-ray.soft double nullable nh Hydrogen Column Density (cm^-2) H-atoms/cm^2 phys.columnDensity double nullable hardness_ratio Hardness Ratio phot.count;arith.ratio;em.X-ray double nullable uhb_counts Ultra-Hard-Band (4-7keV) Counts ct phot.count;em.X-ray.medium double nullable nh_limit Limit Flag for NH meta.code;phys.columnDensity char nullable ref_optical_id Source of Optical Identification meta.ref;phot.mag;em.opt.R short nullable lii Galactic Longitude degree pos.galactic.lon double nullable flux_pos_err Upper Error on 0.5-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray double nullable sb_flux_limit Limit Flag for 0.5-2keV Flux meta.code;phot.flux;em.X-ray.soft char nullable hb_flux_neg_err Lower Error on 2-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable uhb_flux_neg_err Lower RMS Uncertainty on 5-10keV Flux (erg/s/cm^2) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable alt_name Alternative Source Designation meta.id char 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 off_set X-Ray/Optical Centroid Offset (arcsec) arcsec pos.angDistance;em.X-ray;em.opt double nullable