Galactic Center Chandra X-Ray Point Source Catalog

Galactic Center Chandra X-Ray Point Source Catalog GALCENCXO ivo://nasa.heasarc/galcencxo NASA/GSFC HEASARC Muno et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains a catalog of 9017 X-ray sources identified in Chandra observations of a 2 degrees by 0.8 degrees field around the Galactic center. This enlarges the number of known X-ray sources in the region by a factor of 2.5. The catalog incorporates all of the ACIS-I observations as of 2007 August, which total 2.25 Ms of exposure. At the distance to the Galactic center (8 kpc), we are sensitive to sources with luminosities of 4 x 1032 erg s-1 (0.5-8.0 keV; 90% confidence) over an area of 1 degree2, and up to an order of magnitude more sensitive in the deepest exposure (1.0 Ms) around Sgr A*. The positions of 60% of the sources are accurate to <1 arcsecond (95% confidence), and 20% have positions accurate to <0.5 arcsec. The authors search for variable sources, and find that 3% exhibit flux variations within an observation, and 10% exhibit variations from observation-to-observation. They also find one source, CXOUGC J174622.7-285218, with a periodic 1745 s signal (1.4% chance probability), which is probably a magnetically accreting cataclysmic variable. The authors compare the spatial distribution of X-ray sources to a model for the stellar distribution, and find 2.8 sigma evidence for excesses in the numbers of X-ray sources in the region of recent star formation encompassed by the Arches, Quintuplet, and Galactic center star clusters. These excess sources are also seen in the luminosity distribution of the X-ray sources, which is flatter near the Arches and Quintuplet than elsewhere in the field. These excess point sources, along with a similar longitudinal asymmetry in the distribution of diffuse iron emission that has been reported by other authors, probably have their origin in the young stars that are prominent at a galactic lonitude ~ 0.1 degrees. This tables was designed to be inclusive, so sources of questionable quality are included, according to the authors. For instance, 134 sources have net numbers of counts in the 0.5-8.0 keV band that are consistent with 0 at the 90% confidence level. These sources are only detected in a single band and are presumably either very hard or very soft, detected in single observations because they were transients, or detected in stacked observations with wvdecomp at marginal significance. The authors have chosen to include them because they passed the test based on Poisson statistics from Weisskopf et al. (2007, ApJ, 657, 1026). The observations which were used to generate the source list herein tabulated are listed in Table 1 of the reference paper. This HEASARC table GALCENCXO supercedes and replaces the previous HEASARC tables CHANGALCEN and CHANC150PC, which were based on Muno et al. (2003, ApJ, 589, 225) and Muno et al. (2006, ApJS, 165, 173), respectively. This table was created by the HEASARC in March 2009 based on the machine-readable versions of Table 2, 3 and 4 from the paper which were obtained from the electronic ApJ website. The information on short-term variability given in Table 5 of the reference paper was not included in this HEASARC table, notice. This is a service provided by NASA HEASARC . 2009ApJS..181..110M https://heasarc.gsfc.nasa.gov/W3Browse/all/galcencxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=galcencxo& GET text/xml 180 99999 true 265.96232 -29.98648 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=galcencxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_galcencxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 X-ray public galcencxo Galactic Center Chandra X-Ray Point Source Catalog name IAU-Style Source Designation (CXOUGC 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 error_radius Positional Uncertainty (95% Confidence) (arcsec) arcsec stat.error;pos double nullable hb_counts_limit Limit Flag for 2-8 keV Net Counts meta.code;phot;em.X-ray.medium char nullable hb_counts Net Counts in 2-8 keV in Source Region ct phot;em.X-ray.medium double nullable hb_counts_pos_err Upper Uncertainty for 2-8 keV Net Counts (90% confidence) ct stat.error;phot;em.X-ray.medium double nullable hb_counts_neg_err Lower Uncertainty for 2-8 keV Net Counts (90% confidence) ct stat.error;phot;em.X-ray.medium 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 psf_energy Energy at Which PSF Was Estimated keV phys.energy double nullable st_var_flag Flag [YN] Indicates an Observation Detected Variability meta.code;src.var char nullable sb_counts Net Counts in 0.5-2.0 keV in Source Region ct phot;em.X-ray.soft double nullable hr1_neg_err Lower Uncertainty for HR1 stat.error;phot.flux;arith.ratio;em.X-ray double nullable exposure Live Time at Source Position (s) s time.duration;obs.exposure int nullable location_flag Flag Indicates Location: Foreground (f) or Galactic Center (gc) meta.code char nullable num_obs Number of Observations Covering Source meta.number;obs short nullable hr2_neg_err Lower Uncertainty for HR2 stat.error;phot.flux;arith.ratio;em.X-ray double nullable sb_photon_flux Photon Flux in the 0.5-2.0 keV Energy Range photon/cm^2/s phot.flux;em.X-ray.medium double nullable bii Galactic Latitude degree pos.galactic.lat double nullable sb_bck_counts Background Counts in 0.5-2.0 keV in Source Region ct phot;instr.background;em.X-ray.soft double nullable hr1 Medium Color phot.flux;arith.ratio;em.X-ray double nullable sb_counts_limit Limit Flag for 0.5-2.0 keV Net Counts meta.code;phot;em.X-ray.soft char nullable lt_max_min_ratio Ratio of Minimum to Maximum Flux phot.flux;arith.ratio;em.X-ray double nullable detect_band Band in Which Source Was Detected meta.code char nullable hr0_neg_err Lower Uncertainty for HR0 stat.error;phot.flux;arith.ratio;em.X-ray double nullable lt_min_flux Minimum Flux photon/cm^2/s phot.flux;em.X-ray double nullable hb_raw_counts Total Counts in 2-8 keV in Source Region ct phot;em.X-ray.medium int nullable hb_photon_flux Photon Flux in the 2-8 keV Energy Range photon/cm^2/s phot.flux;em.X-ray.medium double nullable lt_max_min_ratio_neg_err Lower Uncertainty for Ratio of Minimum to Maximum Flux stat.error;phot.flux;arith.ratio;em.X-ray double nullable lt_max_flux Maximum Flux photon/cm^2/s phot.flux;em.X-ray double nullable log_bck_match_prob Log of Probability That Source and Background Spectrum from Same Distribution stat.probability double nullable position_flag Flag Indicates Method for Deriving Position meta.code char nullable sb_raw_counts Total Counts in 0.5-2.0 keV in Source Region ct phot;em.X-ray.soft int nullable hb_bck_counts Background Counts in 2-8 keV in Source Region ct phot;instr.background;em.X-ray.medium double nullable quality_flags Flags Indicates Quality of Source meta.code.qual char nullable lt_max_min_ratio_limit Limit Flag for Ratio of Minimum to Maximum Flux meta.code;phot.flux;arith.ratio;em.X-ray char nullable sb_counts_pos_err Upper Uncertainty for 0.5-2.0 keV Net Counts (90% Confidence) ct stat.error;phot;em.X-ray.soft double nullable lt_min_observation Observation with Lowest Measured Flux meta.id;obs char nullable lii Galactic Longitude degree pos.galactic.lon double nullable limiting_photon_flux Completeness Limit (50%) at Source Position photon/cm^2/s phot.flux;em.X-ray double nullable lt_max_flux_error Uncertainty for Maximum Flux (1 Sigma) photon/cm^2/s stat.error;phot.flux;em.X-ray double nullable mean_photon_energy Background-Corrected Mean Observed Photon Energy (keV) keV phys.energy double nullable hr1_pos_err Upper Uncertainty for HR1 stat.error;phot.flux;arith.ratio;em.X-ray double nullable hr2_pos_err Upper Uncertainty for HR2 stat.error;phot.flux;arith.ratio;em.X-ray double nullable hr0 Soft Color phot.flux;arith.ratio;em.X-ray double nullable psf_fraction Fraction of PSF Encompassed by Source Region instr.det.psf double nullable hr0_pos_err Upper Uncertainty for HR0 stat.error;phot.flux;arith.ratio;em.X-ray double nullable off_axis Offset from Aimpoint (arcmin) arcmin instr.offset double nullable lt_min_flux_error Uncertainty for Minimum Flux (1 Sigma) photon/cm^2/s stat.error;phot.flux;em.X-ray double nullable sb_counts_neg_err Lower Uncertainty for 0.5-2.0 keV Net Counts (90% Confidence) ct stat.error;phot;em.X-ray.soft double nullable field_id Field in Which Source Was Detected char nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable hr2 Hard Color phot.flux;arith.ratio;em.X-ray double nullable lt_max_min_ratio_pos_err Upper Uncertainty for Ratio of Minimum to Maximum Flux stat.error;phot.flux;arith.ratio;em.X-ray double nullable lt_max_observation Observation with Highest Measured Flux meta.id;obs char nullable min_extraction_radius Minimum Radius of Source Extraction Region arcsec phys.angSize double nullable lt_min_flux_limit Limit Flag for Minimum Flux meta.code;phot.flux;em.X-ray char nullable