Chandra ACIS GSG Point-Like X-Ray Source Catalog

Chandra ACIS GSG Point-Like X-Ray Source Catalog CXOGSGSRC ivo://nasa.heasarc/cxogsgsrc NASA/GSFC HEASARC Wang et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The Chandra archival data are a valuable resource for various studies on different X-ray astronomy topics. In this paper, the authors utilize this wealth of information and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 Advanced CCD Imaging Spectrometer observations, which produces 363,530 source detections belonging to 217,828 distinct X-ray sources. This number is twice the size of the Chandra Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors, fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows that 17,828 sources are located within the D25 isophotes of 1,110 galaxies, and 7,504 sources are located between the D25 and 2*D25 isophotes of 910 galaxies. Contamination analysis with the log N-log S relation indicates that 51.3% of objects within 2*D25 isophotes are truly relevant to galaxies, and the "net" source fraction increases to 58.9%, 67.3%, and 69.1% for sources with luminosities above 1037, 1038, and 1039 erg/s, respectively. Among the possible scientific uses of this catalog mentioned in this paper, the authors discuss the possibility of studying intra-observation variability, inter-observation variability, and supersoft sources (SSSs). About 17,092 detected sources above 10 counts are classified as variable in individual observation with the Kolmogorov-Smirnov (K-S) criterion (PK-S < 0.01). There are 99,647 sources observed more than once and 11,843 sources observed 10 times or more, offering a wealth of data with which to explore their long-term variability. There are 1,638 individual objects (~2,350 detections) classified as SSSs. As a quite interesting subclass, detailed studies on X-ray spectra and optical spectroscopic follow-up are needed to categorize these SSSs and pinpoint their properties. In addition, this survey can enable a wide range of statistical studies, such as X-ray activity in different types of stars, X-ray luminosity functions in different types of galaxies, and multi-wavelength identification and classification of different X-ray populations. The ACIS observations were downloaded from the Chandra Data Archive on 2014 December 4, yielding 10,047 ACIS observations. Eighteen observations with PI as "Calibration" or Exposure as zero were excluded. Finally, there are 10,029 ACIS observations containing 4,146 ACIS-I observations and 5,883 ACIS-S observations in our sample. The exposure times for the selected observations cover a range from 50 s to 190 ks, with a total of 221,851 ks. This HEASARC table comprises the list of 218,789 X-ray point sources detected in the Chandra ACIS Survey and listed in the machine-readable version of Table 5 from the reference paper. This number is somewhat larger than the number of independent sources (217,828) stated in the abstract and Section 5 of the reference paper because if a source lies within 2*R25 of more than one galaxy it is listed multiple times, once for each galaxy with which it may be associated. All parameters are the same for such duplicate cases except for the entry_number, alt_name, adopted_distance, luminosity, src_nucleus_offset, norm_src_nucleus_offset and (in some cases) source_type. This table was created by the HEASARC in March 2017 primarily based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/224/40/">CDS Catalog J/ApJS/224/40/</a> file table5.dat, the catalog of X-ray point sources in the Chandra ACIS Survey. The positional information for these sources was taken from <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/224/40/">CDS Catalog J/ApJS/224/40/</a> file table3.dat, the list of separation detections for these X-ray sources, using the first listed detection in each case. This is a service provided by NASA HEASARC . 2016ApJS..224...40W https://heasarc.gsfc.nasa.gov/W3Browse/all/cxogsgsrc.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=cxogsgsrc& GET text/xml 180 99999 true 301.14675 -85.70495 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=cxogsgsrc GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_cxogsgsrc&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public cxogsgsrc Chandra ACIS GSG Point-Like X-Ray Source Catalog name Source Designation (CXOGSG JHHMMSS.s+DDMMSS) meta.id;meta.main char nullable alt_name Galaxy Source Name Numbered Sequentially Based on Maximum Detection Significance meta.id 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 Statistical Positional Error after Kim et al. (2007, J/ApJS/169/401) arcsec stat.error;pos double nullable adopted_distance Distance (Adopted) to the X-Ray Source Mpc pos.distance double nullable lx Maximum Luminosity Among Detections erg/s phys.luminosity;em.X-ray double nullable flux Average Flux Among Detections erg/s/cm^2 phot.flux;em.X-ray double nullable max_significance Maximum Detection Significance stat.likelihood;em.X-ray double nullable flux_max_min_pos_err Lower Uncertainty for Fmax/Fmin stat.error;phot.flux;em.X-ray;arith.ratio double nullable norm_src_nucleus_offset Galaxy Source Nuclear Separation in Units of the Elliptical Radius of the Galaxy pos.angDistance;arith.ratio double nullable source_flag Flag [M] Indicates Projected Overlapping Galaxies meta.code;src char nullable source_type Classification of Source src.class char nullable flux_max_min Fmax/Fmin Ratio phot.flux;em.X-ray;arith.ratio double nullable obs_var_stats Statistics for Variability During Individual Observations Using K-S Criterion meta.code;src.var char nullable bii Galactic Latitude degree pos.galactic.lat double nullable max_counts Maximum Photon Counts Among the Detections ct phot;em.X-ray;stat.max double nullable group_number Group Number of Galaxy meta.id.assoc short nullable flux_max_min_neg_err Upper Uncertainty for Fmax/Fmin stat.error;phot.flux;em.X-ray;arith.ratio double nullable num_observed_to_detected Observed/Detected Statistics meta.number;obs;arith.ratio char nullable entry_number Sequential Identification Number for Each Entry in Catalog meta.id int nullable src_nucleus_offset Galaxy Source Nuclear Separation arcmin pos.angDistance double nullable sqhd_phase_stats Statistics for SSS/QSS/Hard/Dim Phases meta.code;src.var char nullable lii Galactic Longitude degree pos.galactic.lon 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