Using a sample of 3814 quasars from the Early Data Release of the Sloan Digital Sky Survey, we confirm that high-ionization, broad, emission lines such as C IV are significantly blueshifted with respect to low-ionization, broad, emission lines, such as Mg II, which are thought to be close to the systemic redshift. We examine the velocity shifts of the Mg II and C IV emission lines with respect to [O III] and Mg II, respectively. C IV emission line peaks have a range of shifts from a redshift of 500 km s −1 to blueshifts well in excess of 2000 km s −1 as compared to Mg II. We confirm previous results that suggest an anti-correlation between the shift of the C IV emission line peak and the rest equivalent width of the C IV emission line. Furthermore, by creating composite quasar spectra as a function of C IV shift, we are able to study, in detail, the profiles of the line as a function of velocity shift. We find that the apparent shift of the C IV emission line peak is not a shift so much as it is a lack of flux in the red wing for the composite with the largest apparent shift. This observation should strongly constrain models for the broad emission line region in quasars. The emission line blueshift and equivalent width of C IV are also discussed in light of the well-known anti-correlation between the equivalent width of C IV emission and continuum luminosity, otherwise known as the Baldwin Effect. We further discuss the C IV emission line shift as a function of other quasar properties such as spectral index, radio and X-ray detection. We find a possible correlation between the C IV emission line shifts and the radio properties of the quasars

We investigate the continuum and emission-line properties of 224 broad absorption line quasars (BALQSOs) with 0.9

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 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, 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 Mg ii 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

We investigate the overall continuum and emission-line properties of quasars as a function of their optical/ UV spectral energy distributions. Our sample consists of 4576 quasars from the Sloan Digital Sky Survey (SDSS) that were chosen using homogeneous selection criteria. Expanding on our previous work, which demonstrated that the optical/UV color distribution of quasars is roughly Gaussian but with a red tail, here we distinguish between (1) quasars that have intrinsically blue (optically flat) power-law continua, (2) quasars that have intrinsically red (optically steep) power-law continua, and (3) quasars whose colors are inconsistent with a single power-law continuum. We find that 273 (6.0%) of the quasars in our sample fall into the latter category and appear to be redder because of SMC-like dust extinction and reddening rather than because of synchrotron emission. Even though the SDSS quasar survey is optically selected and flux-limited, we demonstrate that it is sensitive to dust reddened quasars with E(BÀV ) d 0.5, assuming a classical SMC extinction curve. The color distribution of our SDSS quasar sample suggests that the population of moderately dust reddened, but otherwise normal (i.e., type 1) quasars is smaller than the population of unobscured quasars: we estimate that a further 10% of the quasar population with M i < À25.61 is missing from the SDSS sample because of extinction, bringing the total fraction of dust-reddened quasars to 15% of broad-line quasars. We also investigate the emission-and absorption-line properties of these quasars as a function of color and comment on how some of these results relate to Boroson-Green-type eigenvectors. Quasars with intrinsically red (optically steep) powerlaw continua tend to have narrower Balmer lines and weaker C iv, C iii], He ii, and 3000 Å bump emission as compared with bluer (optically flatter) quasars. The change in strength of the 3000 Å bump appears to be dominated by the Balmer continuum and not by Fe ii emission. The dust-reddened quasars have even narrower Balmer lines and weaker 3000 Å bumps, in addition to having considerably larger equivalent widths of [O ii] and [O iii] emission. The fraction of broad absorption line quasars (BALQSOs) increases from $3.4% for the bluest quasars to perhaps as large as 20% for the dust-reddened quasars, but the intrinsic color distribution will be much bluer if all BALQSOs are affected by dust reddening.

We present a catalog of 224 broad absorption line quasars (BALQSOs) from the Sloan Digital Sky Survey's Early Data Release Quasar Catalog, including a relatively complete and homogeneous subsample of 131 BALQSOs. Since the identification of BALQSOs is subject to considerable systematic uncertainties, we attempt to create a complete sample of SDSS BALQSOs by combining the results of two automated selection algorithms and a by-eye classification scheme. One of these automated algorithms finds broad absorption line troughs by comparison with a composite quasar spectrum. We present the details of this algorithm and compare this method to that which uses a power-law fit to the continuum. The BALQSOs in our sample are further classified as high-ionization BALQSOs (HiBALs), low-ionization BALQSOs (LoBALs), and BALQSOs with excited iron absorption features (FeLoBALs); composite spectra of each type are presented. We further present a study of the properties of the BALQSOs in terms of the