Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog

Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalog SWSDSSQSO ivo://nasa.heasarc/swsdssqso NASA/GSFC HEASARC Wu et al. 2026-05-08 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Quasar The authors have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~ 60% which rises to ~ 85% among sources with at least 10 ks of XRT exposure time. The authors construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, they find that the big blue bump contributes about ~ 0.3 dex to the quasar luminosity. The authors re-visit the alphaox - L2500A relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data. They find only a weak correlation between Lbol/LEdd and alphaUV. They do not find significant correlations between alphax and alphaox, alphaox and alphaUV, and alphax and log L(0.3-10 keV). The correlations between alphaUV and alphax, alphaox and alphax, alphaox and alphaUV, Lbol/LEdd and alphax, and Lbol/LEdd and alphaox are stronger among low-redshift quasars, indicating that these correlations are likely driven by the changes of SED shape with accretion state. This quasar sample was compiled in the following steps: 1. Candidate objects for the catalog were selected as any SDSS DR5 quasar that lie within 20 arcminutes of the center of the Swift FOV in any pointing from launch through 2008 June. 2. XRT data were processed to obtain X-ray count rates, spectra, and spectral parameters. 3. UVOT data were processed to obtain UV and optical photometry. 4. UVOT photometry were supplemented with measurements at other wavelengths from published catalogs. 5. Quasar SEDs were constructed. 6. Additional parameters were calculated based on the SEDs of each quasar. The raw sample is constructed by matching 3.5 years Swift pointings and the SDSS DR5 quasar catalog and contains 1034 objects. This HEASARC version of this catalog contains all 1034 objects in the "raw" catalog. To select only the 843 objects in the "final" catalog, the user should specify catalog_flag = 1 in any searches of this table. This table was created by the HEASARC in August 2012 based on an electronic version of Table 8 from the reference paper which was obtained from the ApJS web site. This is a service provided by NASA HEASARC . 2012ApJS..201...10W https://heasarc.gsfc.nasa.gov/W3Browse/all/swsdssqso.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=swsdssqso& GET text/xml 180 99999 true 347.969413 -10.164718 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=swsdssqso GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_swsdssqso&Action=More+Options&Action=Parameter+Search&ConeAdd=1 SWIFT 0.0166666666666667 Optical UV X-ray public swsdssqso Swift Simultaneous UV, Optical, and X-Ray Observed Quasar Catalo name SDSS DR5 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 umag Best PSF u Band Magnitude mag phot.mag;em.opt.U double nullable redshift SDSS DR5 Quasar Catalog Redshift src.redshift double nullable log_lx Integrated 0.3-10 keV Luminosity log(erg/s) phys.luminosity;em.X-ray double nullable log_l_2500a Logarithm of 2500-Angstrom Monochromatic Luminosity log(erg/s/Hz) phys.luminosity;em.UV.200-300nm double nullable log_l_2500a_error The 1-Sigma Uncertainty in Logarithm of 2500-Angstrom Monochromatic Luminosity log(erg/s/Hz) stat.error;phys.luminosity;em.UV.200-300nm 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 Column Density cm^-2 phys.columnDensity double nullable uv_spectral_index UV Spectral Index by Fitting Photometric Data spect.index;em.UV double nullable sdss_fit_flag Boolean Flag [01] Indicates SDSS Spectrum Is Fit meta.code short nullable uvm2_mag_exposure Total Swift UVM2 Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable log_lbol_exp Logarithm of EXP Model Bolometric Luminosity log(erg/s) phys.luminosity double nullable log_uvw2_flux_dens Logarithm of Swift UVW2 Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.UV.200-300nm double nullable log_uvw1_flux_dens Logarithm of Swift UVW1 Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.UV.200-300nm double nullable xrt_detection_flag XRT Detection Flag meta.code short nullable log_vmag_flux_dens Logarithm of Swift V Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.opt.V double nullable log_l_2kev_error The 1-Sigma Uncertainty in the Logarithm of 2 keV Monochromatic Luminosity log(erg/s/Hz) stat.error;phys.luminosity;em.X-ray double nullable xrt_count_rate XRT Source Count Rate ct/s phot.count;em.X-ray double nullable xrt_exposure Total XRT Exposure Time s time.duration;obs.exposure;em.X-ray double nullable log_fx Logarithm of Unabsorbed 0.3-10 keV Flux log(erg/s/cm^2) phot.flux;em.X-ray double nullable quasar_type Classification of Quasar src.class char nullable bmag_flag Swift B Band Photometry Flag meta.code;phot.flux.density;em.opt.B short nullable log_uvm2_flux_dens Logarithm of Swift UVM2 Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.UV.200-300nm double nullable xrt_photon_index XRT Photon Index Between 0.3 and 10 keV spect.index;meta.modelled;em.X-ray double nullable nh_int Intrinsic Column Density cm^-2 phys.columnDensity double nullable uvm2_mag_flag Swift UVM2 Band Photometry Flag meta.code;phot.flux.density;em.UV.200-300nm short nullable xrt_photon_index_neg_err The 1-Sigma Lower Error for the XRT Photon Index stat.error;spect.index;meta.modelled;em.X-ray double nullable log_l_2kev Logarithm of 2 keV Monochromatic Luminosity log(erg/s/Hz) phys.luminosity;em.X-ray double nullable xrt_photon_index_pos_err The 1-Sigma Upper Error for the XRT Photon Index stat.error;spect.index;meta.modelled;em.X-ray double nullable log_uvw1_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift UVW1 Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.UV.200-300nm double nullable catalog_flag Boolean Flag Indicates Entry Included in Final Catalog meta.code short nullable umag_flag Swift U Band Photometry Flag meta.code;phot.flux.density;em.opt.U short nullable quality_flag Flag [abcd] Indicates Data Quality meta.code.qual char nullable log_black_hole_mass Logarithm of Black Hole Mass log(Solar_Mass) phys.mass double nullable uvw1_mag_flag Swift UVW1 Band Photometry Flag meta.code;phot.flux.density;em.UV.200-300nm short nullable bii Galactic Latitude degree pos.galactic.lat double nullable log_umag_flux_dens Logarithm of Swift U Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.opt.U double nullable bmag_exposure Total Swift B Band Exposure Time s time.duration;obs.exposure;em.opt.B double nullable log_uvw2_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift UVW2 Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.UV.200-300nm double nullable vmag_exposure Total Swift V Band Exposure Time s time.duration;obs.exposure;em.opt.V double nullable vmag_flag Swift V Band Photometry Flag meta.code;phot.flux.density;em.opt.V short nullable abs_imag SDSS DR5 Quasar Catalog Absolute i Band Magnitude mag phys.magAbs;em.opt.I double nullable class Browse Object Classification src.class short nullable sed_flag Boolean Flag Indicates Entry Has SED Plots meta.code short nullable log_bmag_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift B Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.opt.B double nullable umag_exposure Total Swift U Band Exposure Time s time.duration;obs.exposure;em.opt.U double nullable uv_spectral_index_error The 1-Sigma Uncertainty in alpha stat.error;spect.index;em.UV double nullable log_umag_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift U Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.opt.U double nullable red_flag Boolean Flag [01] Indicates Color Is Red meta.code short nullable log_vmag_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift V Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.opt.V double nullable xrt_hardness_ratio Hardness Ratio phot.flux;arith.ratio;em.X-ray double nullable nh_int_neg_err The 1-Sigma Lower Error for the Intrinsic Column Density cm^-2 stat.error;phys.columnDensity double nullable log_lbol_tpl Logarithm of TPL Model Bolometric Luminosity log(erg/s) phys.luminosity double nullable nh_int_pos_err The 1-Sigma Upper Error for the Intrinsic Column Density cm^-2 stat.error;phys.columnDensity double nullable uvw2_mag_exposure Total Swift UVW2 Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable num_2mass_datapts Number of 2MASS Photometric Data Points meta.number;obs short nullable log_bmag_flux_dens Logarithm of Swift B Band Flux Density log(erg/s/cm^2/Angstrom) phot.flux.density;em.opt.B double nullable uvw1_mag_exposure Total Swift UVW1 Band Exposure Time s time.duration;obs.exposure;em.UV.200-300nm double nullable xrt_model Flag [abcd] Indicates Model Used to Fit XRT Spectrum meta.code;spect;meta.modelled char nullable alpha_ox Spectral Index Using log_l_2kev and log_l_2500a spect.index;em.UV.200-300nm;em.X-ray double nullable alpha_ox_error The 1-Sigma Uncertainty in alpha_ox stat.error;spect.index;em.UV.200-300nm;em.X-ray double nullable log_uvm2_flux_dens_error The 1-Sigma Uncertainty in the Logarithm of Swift UVM2 Band Flux Density log(erg/s/cm^2/Angstrom) stat.error;phot.flux.density;em.UV.200-300nm double nullable lii Galactic Longitude degree pos.galactic.lon double nullable log_fx_obs Logarithm of Observed 0.3-10 keV Flux log(erg/s/cm^2) phot.flux;em.X-ray double nullable xrt_quality_flag Flag [gawo] Indicates Quality of XRT Data meta.code.qual char nullable num_swift_datapts Number of Swift/UVOT Photometric Data Points meta.number;obs short nullable uvw2_mag_flag Swift UVW2 Band Photometry Flag meta.code;phot.flux.density;em.UV.200-300nm short nullable