SWXCSCAT ivo://nasa.heasarc/swxcscat NASA/GSFC HEASARC Liu et al. 2026-07-17 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions and soft X-ray fluxes for a flux-limited sample of X-ray group and cluster candidates. In Table 3 of the reference paper (available at the HEASARC as the linked table SWXCSOXID), when possible, optical counterparts are given for these candidates. The authors consider the fields with Galactic latitude |b| > 20 degrees so as to avoid regions of high H I column density. They discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable for searching for faint extended sources. The authors finally select ~ 3000 useful fields covering a total solid angle of ~ 400 deg<sup>2</sup>. They identify extended source candidates in the soft-band (0.5-2 keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing the authors to minimize the number of spurious detections and to robustly assess the selection function. The final catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7 x 10<sup>-15</sup> erg/cm<sup>2</sup>/s in the soft band (0.5 - 2.0 keV), and the log N - log S is in very good agreement with previous deep X-ray surveys. In the reference paper, the final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zel'dovich catalogs of clusters. The authors find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, they have collected redshift information for 158 sources (60% of the entire sample). From the entire Swift XRT archive in the period 2005 February-2012 November, the authors have selected all the fields that can be used to build an unbiased, serendipitous X-ray cluster catalog. This table was created by the HEASARC in March 2015 based on an electronic version of Table 2 from the reference paper which was obtained from the CDS as their catalog J/ApJS/216/28 file table2.dat. This is a service provided by NASA HEASARC . 2015ApJS..216...28L https://heasarc.gsfc.nasa.gov/W3Browse/all/swxcscat.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=swxcscat& GET text/xml 180 99999 true 177.406966 -83.765428 0.0833333333333333 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=swxcscat GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_swxcscat&Action=More+Options&Action=Parameter+Search&ConeAdd=1 SWIFT 0.0833333333333333 X-ray public swxcscat Swift X-Ray Telescope Cluster Survey Catalog name Source Designation 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 extraction_radius Effective Radius arcsec phys.angSize;instr.det double nullable exposure Effective Exposure Time s time.duration;obs.exposure double nullable counts Net 0.5-2keV Band Source Counts ct phot;em.X-ray.soft int nullable counts_error 1-Sigma Uncertainty in Net Source Counts ct stat.error;phot;em.X-ray.soft short nullable flux 0.5-2keV Band Flux erg/s/cm^2 phot.flux;em.X-ray.soft double nullable flux_error 1-Sigma Uncertainty in Flux erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft 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 nh_gal Galactic H I Column Density cm^-2 phys.columnDensity double nullable bii Galactic Latitude degree pos.galactic.lat double nullable source_flag Flag [I] Indicates Source Included in First Release of SWXCS meta.code;src char nullable lii Galactic Longitude degree pos.galactic.lon double nullable snr Signal-to-Noise in 0.5-2 keV Band stat.snr;phot;em.X-ray.soft double nullable