ROS13HRCXO ivo://nasa.heasarc/ros13hrcxo NASA/GSFC HEASARC McHardy et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains some of the results from a Chandra ACIS-I survey of a high-latitude region at RA, Dec = 13 hours, +38 degrees which was earlier observed with ROSAT and which had recently been observed by XMM-Newton for 200 ks. XMM-Newton was expected to provide good-quality X-ray spectra for over 200 sources with fluxes around the knee of the log N /log S distribution, which are responsible for the bulk of the X-ray background. The main aim of the Chandra observations was to provide arcsecond, or better, positions, and hence reliable identifications, for the XMM-Newton sources. The ACIS-I observations were arranged in a mosaic of four 30-ks pointings, covering almost all of the 15-arcminute radius XMM-Newton/ROSAT field. 214 Chandra sources were detected above a Cash likelihood statistic of 25, which approximates to a 5-sigma significance, to a limiting flux of ~ 1.3 x 10<sup>-15</sup>erg/cm<sup>2</sup>/s (0.5 - 7 keV). Optical counterparts were derived from a Subaru SuprimeCam image reaching to R ~ 27. The very large majority of the Chandra sources have an optical counterpart, with the distribution peaking at 23 < R < 24, although 14 have no counterpart to R = 27. The fraction of X-ray sources with no identification brighter than R = 27 is similar to that found in deeper Chandra surveys. The majority of the identifications are with galaxies. As found in other Chandra surveys, there is a very wide range of optical magnitudes for a given X-ray flux, implying a range of emission mechanisms, and many sources have high L<sub>X</sub>/L<sub>opt</sub> ratios, implying absorption at moderate redshift. Comparison with the earlier ROSAT survey shows that the accuracy of the ROSAT positions agrees very well with the predictions from simulations by McHardy et al. and that the large majority of the identifications were correct. This table was created by the HEASARC in July 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/342/802">CDS Catalog J/MNRAS/342/802</a> files table2.dat and table5.dat. This is a service provided by NASA HEASARC . 2003MNRAS.342..802M https://heasarc.gsfc.nasa.gov/W3Browse/all/ros13hrcxo.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=ros13hrcxo& GET text/xml 180 99999 true 203.54629167 37.66301389 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=ros13hrcxo GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_ros13hrcxo&Action=More+Options&Action=Parameter+Search&ConeAdd=1 CHANDRA 0.0166666666666667 Optical X-ray public ros13hrcxo ROSAT/XMM-Newton 13-hour Field Chandra X-Ray Source Catalog source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable name Source Designation meta.id;meta.main char nullable ra Chandra Right Ascension degree pos.eq.ra;meta.main double nullable dec Chandra Declination degree pos.eq.dec;meta.main double nullable flux 0.5-7.0keV Flux erg/s/cm^2 phot.flux;em.X-ray double nullable cash_chi_squared Cash Chi^2 Value for the Chandra Source stat.fit.chi2 double nullable opt_cxo_offset Total Optical-Chandra Offset arcsec pos.angDistance;em.opt;em.X-ray double nullable rmag_limit Limit Flag for R Magnitude of the Optical Counterpart meta.code;phot.mag;em.opt.R char nullable rmag R Magnitude of the Optical Counterpart mag phot.mag;em.opt.R double nullable opt_stellarity Stellarity of the Optical Counterpart: 0 for Galaxy, 1 for Star meta.code 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 rosopt_confirmed_flag Flag [YN?] Indicates Confirmed Source meta.code char nullable alt_cand_flag Flag [UP] Indicates Alternative Optical Candidate meta.code char nullable rosat_dec ROSAT Declination degree pos.eq.dec double nullable opt_fwhm Full Width at Half Maximum arcsec phys.angSize;em.opt double nullable bii Chandra Galactic Latitude degree pos.galactic.lat double nullable source_flag Flag [aco] Indicates Note Concerning Source meta.code;src char nullable cxo_off_axis Chandra Off-Axis Angle of the Source arcmin instr.offset double nullable rosat_ra ROSAT Right Ascension degree pos.eq.ra double nullable rosxmm_off_axis XMM Off-Axis Angle of the Source arcmin instr.offset double nullable lii Chandra Galactic Longitude degree pos.galactic.lon double nullable rosopt_redshift Redshift src.redshift double nullable rosopt_confidence Confidence Parameter from McHardy et al, 1998MNRAS.295..641M meta.code char nullable opt_cxo_offset_ra Optical-Chandra Offset in Right Ascension arcsec pos.angDistance;em.opt;em.X-ray double nullable rosat_source_number ROSAT Unique Identification Number meta.id.cross short nullable rosat_cxo_offset Total ROSAT-Chandra Offset arcsec pos.angDistance;em.X-ray double nullable rosopt_broad_type Broad Classification src.class char nullable opt_cxo_offset_dec Optical-Chandra Offset in Declination arcsec pos.angDistance;em.opt;em.X-ray double nullable rosopt_cxo_offset Total Optical-Chandra Offset arcsec pos.angDistance;em.opt;em.X-ray double nullable