SDSSUNUQSR ivo://nasa.heasarc/sdssunuqsr NASA/GSFC HEASARC Meusinger et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source Large spectroscopic surveys have discovered very peculiar and hitherto unknown types of active galactic nuclei (AGN). Such rare objects may hold clues to the accretion history of the supermassive black holes at the centres of galaxies. The authors aim to create a sizeable sample of unusual quasars from the unprecedented spectroscopic database of the Sloan Digital Sky Survey (SDSS). This table contains a catalog of 1005 quasars with unusual spectra in the redshift interval from 0.6 to 4.3. [HEASARC Note: the redshifts in this table actually range from 0.497 to 4.771]. The quasars were selected from the Sloan Digital Sky Survey Data Release 7 (Abazajian et al., 2009, ApJS, 182, 543) by means of Kohonen self-organising maps. The spectra are dominated by either broad absorption lines (42%), unusual red continua (27%), weak emission lines (18%), or conspicuously strong optical and/or UV iron emission (11%). This large sample provides a useful resource for both studying properties and relations of/between different types of unusual quasars and selecting particularly interesting objects, even though the compilation is not aimed at completeness in a quantifiable sense. The spectra are grouped into seven types. The catalogue contains the redshift, the absolute magnitude, the spectral type, the radio loudness parameter, a peculiarity index, and some comments on peculiar spectral features. This table was created by the HEASARC in May 2012 based on CDS table J/A+A/541/A77 file table3.dat. This is a service provided by NASA HEASARC . 2012A&A...541A..77M https://heasarc.gsfc.nasa.gov/W3Browse/all/sdssunuqsr.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=sdssunuqsr& GET text/xml 180 99999 true 359.63954167 -11.09241667 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=sdssunuqsr GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_sdssunuqsr&Action=More+Options&Action=Parameter+Search&ConeAdd=1 GALAXY CATALOG 0.0166666666666667 Optical public sdssunuqsr Sloan Digital Sky Survey Unusual Quasars Catalog name SDSS 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 redshift Redshift from Present Study src.redshift double nullable imag_0 i Magnitude, Corrected for Galactic Extinction mag phot.mag;em.opt.I double nullable first_flux_20_cm FIRST 1.4-GHz Peak Flux mJy phot.flux.density;em.radio.750-1500MHz double nullable highest_sig_type Number [0-7] Indicates Type of Highest Significance meta.code;src.class short nullable median_sig_type Number [0-7] Indicates Type of Median Significance meta.code;src.class short nullable lowest_sig_type Number [0-7] Indicates Type of Lowest Significance meta.code;src.class short nullable bii Galactic Latitude degree pos.galactic.lat double nullable radio_loudness Radio Loudness Parameter meta.code double nullable comments Comments meta.note char nullable abs_imag Absolute i Magnitude mag phys.magAbs;em.opt.I double nullable source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable first_det_flag Flag [01] Indicates FIRST Detection mag meta.code short nullable qcdr7_flag Flag [012] Indicates QCDR7 Catalog meta.code short nullable redshift_flag Flag [0123] Indicates Redshift Uncertainty meta.code;src.redshift short nullable lii Galactic Longitude degree pos.galactic.lon double nullable peculiarity_index Peculiarity Index meta.code;src.class short 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