SDSSBALQSO ivo://nasa.heasarc/sdssbalqso NASA/GSFC HEASARC Trump et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The Sloan Digital Sky Survey (SDSS) Broad Absorption Line (BAL) Quasars Catalog (based on the 3rd SDSS Data Release) contains a total of 4784 unique BAL quasars from the SDSS DR3 (<a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/243">CDS Cat. <VII/243></a>). An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the continuum over a velocity range of at least 1000 km/s in the C IV and Mg II absorption regions. The model continuum was selected as the best-fit match from a set of template quasar spectra binned in luminosity, emission line width, and redshift z, with the power-law spectral index and amount of dust reddening as additional free parameters. The authors characterize their sample through the traditional 'balnicity' index BI and a revised absorption index AI, as well as through parameters such as the width, outflow velocity, fractional depth, and number of troughs. From a sample of 16,883 quasars at 1.7 <= z <= 4.38, they identify 4386 (26.0%) quasars with broad C IV absorption, of which 1756 (10.4%) satisfy traditional selection criteria. From a sample of 34,973 quasars at 0.5 <= z <= 2.15, they identify 457 (1.31%) quasars with broad Mg II absorption, 191 (0.55%) of which satisfy traditional selection criteria. They find that BAL quasars may have broader emission lines on average than other quasars. Much more information on the SDSS is available at the project's web site at <a href="http://www.sdss.org/">http://www.sdss.org/</a>. This table was created by the HEASARC in July 2008 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/165/1">CDS catalog J/ApJS/165/1</a> file table4.dat. This is a service provided by NASA HEASARC . 2006ApJS..165....1T https://heasarc.gsfc.nasa.gov/W3Browse/all/sdssbalqso.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=sdssbalqso& GET text/xml 180 99999 true 7.3395 -11.09775 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=sdssbalqso GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_sdssbalqso&Action=More+Options&Action=Parameter+Search&ConeAdd=1 GALAXY CATALOG 0.0166666666666667 Optical public sdssbalqso Sloan Digital Sky Survey Broad Absorption Line Quasars Catalog: name SDSS DR3 Source Designation (SDSS JHHMMSS.ss+DDMMSS.s) 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 redshift Redshift src.redshift double nullable imag SDSS PSF i Magnitude mag phot.mag;em.opt.I double nullable abs_imag Absolute i Magnitude mag phys.magAbs;em.opt.I double nullable bal_subtype Classification Subtype src.class char nullable deepest_bal_trough Deepest Part of Any BAL Trough phot.flux;arith.ratio double nullable spect_fiber_number Spectroscopic Fiber Number meta.id;instr.param short nullable absorption_index_error Error in Absorption Index km/s stat.error;phys.absorption double nullable balnicity_index_error Error in Balnicity Index km/s stat.error;spect.line.eqWidth double nullable bii Galactic Latitude degree pos.galactic.lat double nullable spect_date Date of Spectroscopic Observation mjd time.start;obs;spect int nullable max_bal_velocity Maximum Velocity of BAL Troughs from the Emission Line (km/s) km/s spect.dopplerVeloc int nullable spectral_index Spectral Index Used by Best-Fitted Template spect.index double nullable best_fit_template Best-Fit Template Number meta.code short nullable reddening Reddening Used by Best-Fitted Template phot.color.excess double nullable wtd_average_velocity Weighted Average Velocity of BAL Troughs (km/s) km/s spect.dopplerVeloc int nullable reduced_chi_squared Reduced Chi^2 Value of the Best Fit stat.fit.chi2 double nullable widest_bal_trough Widest BAL Trough km/s spect.dopplerVeloc int nullable balnicity_index Balnicity Index km/s spect.line.eqWidth int nullable number_bal_trough Number of Distinct BAL Troughs meta.number short nullable lii Galactic Longitude degree pos.galactic.lon double nullable spect_plate_number Spectroscopic Plate Number meta.id;instr.plate short nullable imag_band_snr SDSS Spectrum S/N Ratio in the i-Band stat.snr;em.opt.I double nullable absorption_index Absorption Index km/s phys.absorption int 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