GALCCXONID ivo://nasa.heasarc/galccxonid NASA/GSFC HEASARC Mauerhan et al. 2026-10-02 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Infrared Counterpart This table contains a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2 degrees x 0.8 degrees of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. The authors have cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10-sigma limiting flux of K<sub>s</sub> <= 15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, they defined red and blue sources as those which have H - K<sub>s</sub> >= 0.9 and < 0.9 mag, respectively. The authors find that 5.8% =/- 1.5% (2 sigma) of the hard X-ray sources have real infrared counterparts, of which 228 +/- 99 are red and 166 +/- 27 are blue. The red counterparts are probably comprised of Wolf-Rayet and O stars, high-mass X-ray binaries, and symbiotic binaries located near the Galactic center. Foreground X-ray binaries suffering intrinsic X-ray absorption could be included in the sample of blue infrared counterparts to hard X-ray sources. The authors also find that 39.4% +/- 1.0% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ~20 red counterparts to hard X-ray sources near the Sagittarius B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in their catalog, the authors derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis. These data are included in this catalog and will serve spectroscopic surveys to identify infrared counterparts to X-ray sources near the Galactic center. This table was created by the HEASARC in October 2009 based on the electronic version of Table 3 from the reference paper which was obtained from the Astrophysical Journal web site. This is a service provided by NASA HEASARC . 2009ApJ...703...30M https://heasarc.gsfc.nasa.gov/W3Browse/all/galccxonid.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=galccxonid& GET text/xml 180 99999 true 265.9623 -29.98614 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=galccxonid GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_galccxonid&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Infrared X-ray public galccxonid Galactic Center Chandra X-Ray Source Near-IR Counterparts name Catalog Source Designation meta.id;meta.main char nullable cxo_name IAU Designation of X-Ray Source (CXOUGC Jhhmmss.s-ddmmss) meta.id.assoc char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable off_set Angular Separation of X-Ray Source and IR Match (arcsec) arcsec pos.angDistance double nullable match_probability Percent Probability for IR Match stat.probability double nullable jmag J Band Magnitude mag phot.mag;em.IR.J double nullable hmag H Band Magnitude mag phot.mag;em.IR.H double nullable kmag K_s Band Magnitude mag phot.mag;em.IR.K double nullable bck_ir_surf_density Background Surface Density of IR Sources (arcsec^-2) arcsec^-2 meta.code;obs double nullable kmag_error Uncertainty in Kmag mag stat.error;phot.mag;em.IR.K double nullable ir_color_class Color Class of of IR Match (red or blue) src.class;em.IR char nullable hmag_error Uncertainty in Hmag mag stat.error;phot.mag;em.IR.H double nullable xray_error_radius Positional Uncertainty of X-Ray source; 95% arcsec stat.error;pos double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable jmag_error Uncertainty in Jmag mag stat.error;phot.mag;em.IR.J double nullable muno_source_number Muno et al. 2009 X-Ray Source Record Number meta.id.assoc short nullable xray_hardness_class Hardness Class of X-Ray Source (hard or soft) src.class;em.X-ray char nullable bii Galactic Latitude degree pos.galactic.lat double 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