NWAYAWGXMM ivo://nasa.heasarc/nwayawgxmm NASA/GSFC HEASARC Salvato et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the 19,141 AllWISE counterparts and/or Gaia matches to 17,665 X-ray sources detected in the XMM-Newton Slew Survey, Version 2 (hereafter XMMSL2, currently available at the HEASARC as the XMMSLEWCLN table) list of 'Clean' sources that lie at Galactic latitude |b| > 15 degrees. These are among the brightest X-ray sources in the sky, but their position uncertainties and the sparse multi-wavelength coverage until now have rendered the identification of their counterparts a demanding task with uncertain results. New all-sky multi-wavelength surveys of sufficient depth, like AllWISE and Gaia, and a new Bayesian statistics-based algorithm, NWAY, allow us, for the first time, to provide reliable counterpart associations. NWAY extends previous distance- and sky density-based association methods and, using one or more priors (e.g. colors, magnitudes), weights the probability that sources from two or more catalogs are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) color-magnitude prior. A reference sample of 4,524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of 97.4 per cent for XMMSL2 sources. Combining the results of this work and of the matching of ROSAT All-Sky Survey 2RXS sources also reported in this study (the results of the latter are available as the HEASARC's database table NWAYAWGROS) with Chandra-COSMOS data, the authors propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, that is valid over six orders of magnitude. The authors also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data. Using two different sets of priors, the authors find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Their results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.), NWAY will provide a powerful and reliable counterpart identification tool. For all the available options, see the NWAY manual at <a href="https://github.com/JohannesBuchner/nway/raw/master/doc/nway-manual.pdf">https://github.com/JohannesBuchner/nway/raw/master/doc/nway-manual.pdf</a>. This table was created by the HEASARC in February 2018 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/473/4937">CDS catalog J/MNRAS/473/4937</a> file xmmslew2.dat. This is a service provided by NASA HEASARC . 2018MNRAS.473.4937S https://heasarc.gsfc.nasa.gov/W3Browse/all/nwayawgxmm.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=nwayawgxmm& GET text/xml 180 99999 true 333.4588832439 -89.38069038559 0.0333333333333333 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=nwayawgxmm GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_nwayawgxmm&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0333333333333333 Infrared Optical X-ray public nwayawgxmm AllWISE Counterparts and Gaia Matches to XMM-Newton Slew Survey name XMM-Newton Slew Survey (XMMSL2) Source Designation (XMMSL2_ID) 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 flux_b8 XMMSL2 Flux in Band 8 (XMMSL2_FLUX_B8) erg/s/cm^2 phot.flux;em.X-ray double nullable flux_b8_error XMMSL2 Flux Error in Band 8 (XMMSL2_FLUX_ERR_B8) erg/s/cm^2 stat.error;phot.flux;em.X-ray double nullable allwise_name WISE All-Sky Source Designation from Cutri et al. (2013, Cat. II/328) (ALLW_ID) meta.id.cross;em.IR char nullable allwise_xmm_offset Separation Between X-Ray Source and AllWISE Candidate Counterpart arcsec pos.angDistance;em.X-ray;em.IR double nullable w1_mag AllWISE Vega Magnitude in the W1 Band (ALLW_w1mpro) mag phot.mag;em.IR.3-4um double nullable w1_mag_error AllWISE Magnitude Error in the W1 Band (ALLW_w1sigmpro) mag stat.error;phot.mag;em.IR.3-4um double nullable w2_mag AllWISE Vega Magnitude in the W2 Band (ALLW_w2mpro) mag phot.mag;em.IR.4-8um double nullable w2_mag_error AllWISE Magnitude Error in the W2 Band (ALLW_w2sigmpro) mag stat.error;phot.mag;em.IR.4-8um 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 gaia_pm_ra Proper Motion in Right Ascension as Measured by Gaia (pmra) mas/yr pos.pm;pos.eq.ra double nullable ext_b7 XMMSL2 Source Extent in units of Image pixels, in Band 7 (XMMSL2_EXT_B7) pixel phys.angSize;src;em.X-ray.medium double nullable prob_i Relative Probability of the Match (p_i) stat.probability double nullable ext_b8 XMMSL2 Source Extent in units of Image pixels, in Band 8 (XMMSL2_EXT_B8) pixel phys.angSize;src;em.X-ray double nullable gaia_gmag Gaia Mean Magnitude (phot_g_mean_mag) mag phot.mag;em.opt double nullable allwise_error_radius AllWISE Positional Error (ALLW_e_RADEC) arcsec stat.error;pos double nullable flux_b7_error XMMSL2 Flux Error in Band 7 (XMMSL2_FLUX_ERR_B7) erg/s/cm^2 stat.error;phot.flux;em.X-ray.medium double nullable w1_snr AllWISE Signal-to-Noise Ratio in the W1 Band (ALLW_w1snr) stat.snr;em.IR.3-4um double nullable flux_b7 XMMSL2 Flux in Band 7 (XMMSL2_FLUX_B7) erg/s/cm^2 phot.flux;em.X-ray.medium double nullable allwise_ra AllWISE Right Ascension (ALLW_RA) degree pos.eq.ra double nullable w3_mag_error AllWISE Magnitude Error in the W3 Band (ALLW_w3sigmpro) mag stat.error;phot.mag;em.IR.8-15um double nullable gaia_pm_dec Proper Motion in Declination as Measured by Gaia (pmdec) mas/yr pos.pm;pos.eq.dec double nullable hmag_error 2MASS Magnitude Error in the H Band as Reported in the AllWISE Catalog mag stat.error;phot.mag;em.IR.H double nullable bias Probability Weighting Introduced by AllWISE Prior. (1 Indicates No Change) stat.param double nullable prob_single Same as dist_post, but Weighted by the AllWISE Color-Magnitude Prior. (p_single) stat.probability double nullable gaia_g_band_flux Gaia G-Band Mean Flux (phot_g_mean_flux) electron/s phot.flux;em.opt double nullable number_matches Number of Possible All-WISE Counterparts for a Given X-Ray Source (GroupSize) meta.number short nullable hmag 2MASS Magnitude in the H Band, as from AllWISE Catalog (ALLW_h_m_2mass) mag phot.mag;em.IR.H double nullable w4_snr AllWISE Signal-to-Noise Ratio in the W4 Band (ALLW_w4snr) stat.snr;em.IR.15-30um double nullable jmag_error 2MASS Magnitude Error in the J Band as Reported in the AllWISE Catalog mag stat.error;phot.mag;em.IR.J double nullable gaia_pm_ra_error Proper Motion Error in Right Ascension as Measured by Gaia (pmra_error) mas/yr stat.error;pos.pm;pos.eq.ra double nullable allwise_dec AllWISE Declination (ALLW_DEC) degree pos.eq.dec double nullable bii Galactic Latitude degree pos.galactic.lat double nullable gaia_pm_dec_error Proper Motion Error in Declination as Measured by Gaia (pmdec_error) mas/yr stat.error;pos.pm;pos.eq.dec double nullable ext_ml_b6 Probability of the XMMSL2 Source Extend in Band 6 (XMMSL2_Ext_ML_B6) stat.likelihood;phys.angSize;em.X-ray.soft double nullable det_ml_b8 XMMSL2 Source Detection Likelihood in Band 8 (XMMSL2_DET_ML_B8) stat.likelihood;src;em.X-ray double nullable error_radius XMMSL2 Positional Error (XMMSL2_e_RADEC) arcsec stat.error;pos double nullable ext_ml_b7 Probability of the XMMSL2 Source Extend in Band 7 (XMMSL2_Ext_ML_B7) stat.likelihood;phys.angSize;em.X-ray.medium double nullable w4_mag AllWISE Vega Magnitude in the W4 Band (ALLW_w4mpro) mag phot.mag;em.IR.15-30um double nullable kmag_error 2MASS Magnitude Error in the K Band as Reported in the AllWISE Catalog mag stat.error;phot.mag;em.IR.K double nullable ext_b6 XMMSL2 Source Extent in units of Image pixels, in Band 6 (XMMSL2_EXT_B86) pixel phys.angSize;src;em.X-ray.soft double nullable gaia_dec Gaia Declination (Gaia_DR1_DEC) degree pos.eq.dec double nullable ext_ml_b8 Probability of the XMMSL2 Source Extend in Band 8 (XMMSL2_Ext_ML_B8) stat.likelihood;phys.angSize;em.X-ray double nullable det_ml_b6 XMMSL2 Source Detection Likelihood in Band 6 (XMMSL2_DET_ML_B6) stat.likelihood;src;em.X-ray.soft double nullable twomass_name 2MASS Source Designation as Listed in the AllWISE Catalog (ALLW_2MASS_ID) meta.id.cross;em.IR char nullable flux_b6_error XMMSL2 Flux Error in Band 6 (XMMSL2_FLUX_ERR_B6) erg/s/cm^2 stat.error;phot.flux;em.X-ray.soft double nullable allwise_flags AllWISE Reliability Flag from Cutri et al. (2013, Cat. II/328) (ALLW_cc_flags) meta.code char nullable dist_post Distance Posterior Probability Comparing This Association vs. No Association stat.param double nullable jmag 2MASS Magnitude in the J Band, as from AllWISE Catalog (ALLW_j_m_2mass) mag phot.mag;em.IR.J double nullable lii Galactic Longitude degree pos.galactic.lon double nullable det_ml_b7 XMMSL2 Source Detection Likelihood in Band 7 (XMMSL2_DET_ML_B7) stat.likelihood;src;em.X-ray.medium double nullable group_id Sequential Number for X-Ray Sources with More Than One Possible Counterpart meta.id short nullable dist_bayesfactor Logarithm of Ratio Between Prior and Posterior (dist_bayesfactor) stat.param double nullable gaia_name Identification from Original Gaia DR1 Catalog from Fabricious et al. (2016) meta.id.cross;em.opt char nullable prob_any Probability That There Is a Counterpart for Each X-Ray Source (p_any) stat.probability double nullable gaia_ra Gaia Right Ascension (Gaia_DR1_RA) degree pos.eq.ra double nullable w3_mag AllWISE Vega Magnitude in the W3 Band (ALLW_w3mpro) mag phot.mag;em.IR.8-15um double nullable w4_mag_error AllWISE Magnitude Error in the W4band (ALLW_w4sigmpro) mag stat.error;phot.mag;em.IR.15-30um double nullable match_flag Quality of the X-Ray to WISE Association meta.code short nullable w3_snr AllWISE Signal-to-Noise Ratio in the W3 Band (ALLW_w3snr) stat.snr;em.IR.8-15um double nullable onerxs_name Source Designation in the 1RXS Catalogs of Voges et al. (1999 and 2000) meta.id.cross;em.X-ray.soft char nullable kmag 2MASS Magnitude in the K Band, as from AllWISE Catalog (ALLW_k_m_2mass) mag phot.mag;em.IR.K double nullable gaia_g_band_flux_error Gaia G-Band Mean Flux Error (phot_g_mean_flux_error) electron/s stat.error;phot.flux;em.opt double nullable w2_snr AllWISE Signal-to-Noise Ratio in the W2 Band (ALLW_w2snr) stat.snr;em.IR.4-8um double nullable flux_b6 XMMSL2 Flux in Band 6 (XMMSL2_FLUX_B6) erg/s/cm^2 phot.flux;em.X-ray.soft double nullable