The Sloan Digital Sky Survey quasar catalog: ninth data release

We present the Data Release 9 Quasar (DR9Q) catalog from the BaryonOscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky SurveyIII. The catalog includes all BOSS objects that were targeted as quasarcandidates during the survey, are spectrocopically confirmed as quasarsvia visual inspection, have luminosities M_i[z = 2] -20.5(in a ΛCDM cosmology with H₀ = 70 km s^-1Mpc^-1, Ω_M = 0.3, andΩ_Λ = 0.7) and either display at least oneemission line with full width at half maximum (FWHM) larger than 500 kms^-1 or, if not, have interesting/complex absorption features.It includes as well, known quasars (mostly from SDSS-I and II) that werereobserved by BOSS. This catalog contains 87 822 quasars (78 086 are newdiscoveries) detected over 3275 deg² with robustidentification and redshift measured by a combination of principalcomponent eigenspectra newly derived from a training set of 8632 spectrafrom SDSS-DR7. The number of quasars with z > 2.15 (61 931) is ~2.8times larger than the number of z > 2.15 quasars previously known.Redshifts and FWHMs are provided for the strongest emission lines (C iv,C iii], Mg ii). The catalog identifies 7533 broad absorption linequasars and gives their characteristics. For each object the catalogpresents five-band (u, g, r, i, z) CCD-based photometry with typicalaccuracy of 0.03 mag, and information on the morphology and selectionmethod. The catalog also contains X-ray, ultraviolet, near-infrared, andradio emission properties of the quasars, when available, from otherlarge-area surveys. The calibrated digital spectra cover the wavelengthregion 3600-10 500 Å at a spectral resolution in the range 1300 R 2500; the spectra can be retrieved from the SDSS CatalogArchive Server. We also provide a supplemental list of an additional 949quasars that have been identified, among galaxy targets of the BOSS oramong quasar targets after DR9 was frozen.Catalog is only available at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/548/A66