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Date and Time of the Query: 2019-08-18 T13:04:14 PDT
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For refcode 2015AJ....149..203K:
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2015AJ....149..203K Mining for Dust in Type 1 Quasars Krawczyk, Coleman M.; Richards, Gordon T.; Gallagher, S. C.; Leighly, Karen M.; Hewett, Paul C.; Ross, Nicholas P.; Hall, P. B. Abstract. We explore the extinction/reddening of ~35,000 uniformly selected quasars with 0\lt z<=slant 5.3 in order to better understand their intrinsic optical/ultraviolet (UV) spectral energy distributions. Using rest-frame optical--UV photometry taken from the Sloan Digital Sky Survey's (SDSS) 7th data release, cross-matched to WISE in the mid-infrared, 2MASS and UKIDSS in the near-infrared, and GALEX in the UV, we isolate outliers in the color distribution and find them well described by an SMC-like reddening law. A hierarchical Bayesian model with a Markov Chain Monte Carlo sampling method was used to find distributions of power law indices and E(B-V) consistent with both the broad absorption line (BAL) and non-BAL samples. We find that, of the ugriz color-selected type 1 quasars in SDSS, 2.5% (13%) of the non-BAL (BAL) sample are consistent with E(B-V)\gt 0.1 and 0.1% (1.3%) with E(B-V)\gt 0.2. Simulations show both populations of quasars are intrinsically bluer than the mean composite, with a mean spectral index ({{alpha}_lambda_}) of -1.79 (-1.83). The emission and absorption-line properties of both samples reveal that quasars with intrinsically red continua have narrower Balmer lines and stronger high-ionization emission lines, the latter indicating a harder continuum in the extreme-UV and the former pointing to differences in black hole mass and/or orientation. Key words: dust, extinction, infrared: galaxies, methods: statistical, quasars: absorption lines, quasars: emission lines, quasars: general =========================================================================== 2016AJ....151...20K Erratum: "Mining for Dust in Type 1 Quasars" (2015, AJ, 149, 203) Krawczyk, Coleman M.; Richards, Gordon T.; Gallagher, S. C.; Leighly, Karen M.; Hewett, Paul C.; Ross, Nicholas P.; Hall, P. B. Abstract. After this paper was published I noticed that several of the columns in Table 2 were incorrect. The covariance matrix values for L14-QSO were repeats of the values for the SMC. The corrected table {see Table 2.} ===========================================================================
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