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We present a total of 4784 unique broad absorption line quasars from the Sloan Digital Sky Survey Third Data Release. 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 −1 in the Civ and Mgii 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, with the power-law spectral index and amount of dust reddening as additional free parameters. We characterize our sample through the traditional “balnicity ” index and a revised absorption index, as well as through parameters such as the width, outflow velocity, fractional depth and number of troughs. From a sample of 16883 quasars at 1.7 ≤ z ≤ 4.38, we identify 4386 (26.0%) quasars with broad Civ absorption, of which 1756 (10.4%) satisfy traditional selection criteria. From a sample of 34973 quasars at 0.5 ≤ z ≤ 2.15, we identify 457 (1.31%) quasars with broad Mgii absorption, 191 (0.55%) of which satisfy traditional selection criteria. We also provide a supplementary list of 39 visually identified z 4.38 quasars with broad Civ absorption. We find 1
Trump et al. (Sat,) studied this question.