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1651. SDSS quasar catalog: twelfth data release
ID:
ivo://CDS.VizieR/VII/279
Title:
SDSS quasar catalog: twelfth data release
Short Name:
VII/279
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Data Release 12 Quasar catalog (DR12Q) from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky SurveyIII. This catalog includes all SDSS-III/BOSS objects that were spectroscopically targeted as quasar candidates during the full survey and that are confirmed as quasars via visual inspection of the spectra, have luminosities M_i_[z=2]< -20.5 (in a {Lambda}CDM cosmology with H_0_=70km/s/Mpc, {Omega}_M_=0.3, and {Omega}_{Lambda}_=0.7), and either display at least one emission line with a full width at half maximum (FWHM) larger than 500km/s or, if not, have interesting/complex absorption features. The catalog also includes previously known quasars (mostly from SDSS-I andII) that were reobserved by BOSS. The catalog contains 297 301 quasars (272 026 are new discoveries since the beginning of SDSS-III) detected over 9376deg^2^ with robust identification and redshift measured by a combination of principal component eigenspectra. The number of quasars with z>2.15 (184 101, of which 167 742 are new discoveries) is about an order of magnitude greater than the number of z>2.15 quasars known prior to BOSS. Redshifts and FWHMs are provided for the strongest emission lines (CIV, CIII], MgII). The catalog identifies 29 580 broad absorption line quasars and lists their characteristics. For each object, the catalog presents five-band (u, g, r, i, z) CCD-based photometry with typical accuracy of 0.03mag together with some information on the optical morphology and the selection criteria. When available, the catalog also provides information on the optical variability of quasars using SDSS and Palomar Transient Factory multi-epoch photometry. The catalog also contains X-ray, ultraviolet, near-infrared, and radio emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra, covering the wavelength region 3600-10 500{AA} at a spectral resolution in the range 1300<R<2500, can be retrieved from the SDSS Catalog Archive Server. We also provide a supplemental list of an additional 4841 quasars that have been identified serendipitously outside of the superset defined to derive the main quasar catalog.
1652. SDSS Quasar Lens Search. IV.
ID:
ivo://CDS.VizieR/J/AJ/140/403
Title:
SDSS Quasar Lens Search. IV.
Short Name:
J/AJ/140/403
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the second report of our systematic search for strongly lensed quasars from the data of the Sloan Digital Sky Survey (SDSS). From extensive follow-up observations of 136 candidate objects, we find 36 lenses in the full sample of 77,429 spectroscopically confirmed quasars in the SDSS Data Release 5.
1653. SDSS Quasar Lens Search. V. Final catalog
ID:
ivo://CDS.VizieR/J/AJ/143/119
Title:
SDSS Quasar Lens Search. V. Final catalog
Short Name:
J/AJ/143/119
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the final statistical sample of lensed quasars from the Sloan Digital Sky Survey (SDSS) Quasar Lens Search (SQLS). The well-defined statistical lens sample consists of 26 lensed quasars brighter than i=19.1 and in the redshift range of 0.6<z<2.2 selected from 50826 spectroscopically confirmed quasars in the SDSS Data Release 7 (DR7), where we restrict the image separation range to 1"<{theta}<20" and the i-band magnitude differences in two images to be smaller than 1.25mag. The SDSS-DR7 quasar catalog also contains 36 additional lenses identified with various techniques. In addition to these lensed quasars, we have identified 81 pairs of quasars from follow-up spectroscopy, 26 of which are physically associated binary quasars. The statistical lens sample covers a wide range of image separations, redshifts, and magnitudes, and therefore is suitable for systematic studies of cosmological parameters and surveys of the structure and evolution of galaxies and quasars.
1654. SDSS quasars in the COSMOS field
ID:
ivo://CDS.VizieR/J/ApJ/644/100
Title:
SDSS quasars in the COSMOS field
Short Name:
J/ApJ/644/100
Date:
21 Oct 2021
Publisher:
CDS
Description:
We obtained medium-resolution spectra of 336 quasar candidates in the COSMOS HST Treasury field using the MMT 6.5m telescope and the Hectospec multiobject spectrograph. Candidates were drawn from the Sloan Digital Sky Survey (SDSS) DR1 catalog using quasar flags set by the SDSS multicolor quasar target selection algorithm. In this paper we present our discovery spectra from 1.39deg^2^ (69.5% of the COSMOS field) and a discussion of the selection method and yields. We confirmed 95 quasars, including at least two BAL quasars; 80 of these are new quasars that do not appear in previous quasar confirmation follow-up studies. The candidates additionally included 184 compact emission-line galaxies, a third of which are likely type 2 AGNs, and 12 stars. The quasars span a range in magnitude of 18.3<g<22.5 and a range in redshift of 0.2<z<2.3. Our results are consistent with a lower limit quasar surface density from SDSS color selection of 102deg^-2^ down to g=22.5 over the entire COSMOS field. This work is the first step toward the eventual goal of setting up a grid of quasar absorption line probes of the 2deg^2^ field and of conducting a complete census of supermassive black holes in this well-studied survey region. The total quasar count at the conclusion of this study is 139, making COSMOS one of the most densely sampled regions of sky where a grid of quasar sight lines can be used to probe the intervening volume.
1655. SDSS red gal. automated morph. classification
ID:
ivo://CDS.VizieR/J/MNRAS/412/727
Title:
SDSS red gal. automated morph. classification
Short Name:
J/MNRAS/412/727
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the last decade, the advent of enormous galaxy surveys has motivated the development of automated morphological classification schemes to deal with large data volumes. Existing automated schemes can successfully distinguish between early- and late-type galaxies and identify merger candidates, but are inadequate for studying detailed morphologies of red sequence galaxies. To fill this need, we present a new automated classification scheme that focuses on making finer distinctions between early types roughly corresponding to Hubble types E, S0 and Sa. We visually classify a sample of 984 non-star-forming Sloan Digital Sky Survey galaxies with apparent sizes >14-arcsec. We then develop an automated method to closely reproduce the visual classifications, which both provides a check on the visual results and makes it possible to extend morphological analysis to much larger samples. We visually classify the galaxies into three bulge classes (BC) by the shape of the light profile in the outer regions: discs have sharp edges and bulges do not, while some galaxies are intermediate. We separately identify galaxies with features: spiral arms, bars, clumps, rings and dust.
1656. SDSS-RM AGNs CFHT & Bok photometry over 4yrs
ID:
ivo://CDS.VizieR/J/ApJS/250/10
Title:
SDSS-RM AGNs CFHT & Bok photometry over 4yrs
Short Name:
J/ApJS/250/10
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Sloan Digital Sky Survey (SDSS) Reverberation Mapping program monitors 849 active galactic nuclei (AGNs) both spectroscopically and photometrically. The photometric observations used in this work span over 4yr and provide an excellent baseline for variability studies of these objects. We present the photometric light curves from 2014 to 2017 obtained by the Steward Observatory's Bok telescope and the Canada-France-Hawaii telescope with MegaCam. We provide details on the data acquisition and processing of the data from each telescope, the difference imaging photometry used to produce the light curves, and the calculation of a variability index to quantify each AGN's variability. We find that the Welch-Stetson J index provides a useful characterization of AGN variability and can be used to select AGNs for further study.
1657. SDSS RM Project: CIV lags & LCs from 4yrs of data
ID:
ivo://CDS.VizieR/J/ApJ/887/38
Title:
SDSS RM Project: CIV lags & LCs from 4yrs of data
Short Name:
J/ApJ/887/38
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present reverberation-mapping (RM) lags and black hole mass measurements using the CIV{lambda}1549 broad emission line from a sample of 348 quasars monitored as a part of the Sloan Digital Sky Survey RM Project. Our data span four years of spectroscopic and photometric monitoring for a total baseline of 1300 days, allowing us to measure lags up to ~750days in the observed frame (this corresponds to a rest-frame lag of ~300days in a quasar at z=1.5 and ~190days at z=3). We report significant time delays between the continuum and the CIV{lambda}1549 emission line in 48 quasars, with an estimated false-positive detection rate of 10%. Our analysis of marginal lag measurements indicates that there are on the order of ~100 additional lags that should be recoverable by adding more years of data from the program. We use our measurements to calculate black hole masses and fit an updated CIV radius-luminosity relationship. Our results significantly increase the sample of quasars with CIV RM results, with the quasars spanning two orders of magnitude in luminosity toward the high-luminosity end of the CIV radius-luminosity relation. In addition, these quasars are located at some of the highest redshifts (z~1.4-2.8) of quasars with black hole masses measured with RM.
1658. SDSS RM project: continuum lags
ID:
ivo://CDS.VizieR/J/ApJ/880/126
Title:
SDSS RM project: continuum lags
Short Name:
J/ApJ/880/126
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present accretion disk structure measurements from continuum lags in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Lags are measured using the JAVELIN software from the first-year SDSS-RM g and i photometry, resulting in well-defined lags for 95 quasars, 33 of which have lag S/N>2{sigma}. We also estimate lags using the ICCF software and find consistent results, though with larger uncertainties. Accretion disk structure is fit using a Markov chain Monte Carlo approach, parameterizing the measured continuum lags as a function of disk size normalization, wavelength, black hole mass, and luminosity. In contrast with previous observations, our best-fit disk sizes and color profiles are consistent (within 1.5{sigma}) with the Shakura & Sunyaev (1973A&A....24..337S) analytic solution. We also find that more massive quasars have larger accretion disks, similarly consistent with the analytic accretion disk model. The data are inconclusive on a correlation between disk size and continuum luminosity, with results that are consistent with both no correlation and the Shakura & Sunyaev expectation. The continuum lag fits have a large excess dispersion, indicating that our measured lag errors are underestimated and/or our best-fit model may be missing the effects of orientation, spin, and/or radiative efficiency. We demonstrate that fitting disk parameters using only the highest-S/N lag measurements biases best-fit disk sizes to be larger than the disk sizes recovered using a Bayesian approach on the full sample of well-defined lags.
1659. SDSS RM project first year of observations
ID:
ivo://CDS.VizieR/J/ApJ/851/21
Title:
SDSS RM project first year of observations
Short Name:
J/ApJ/851/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present reverberation mapping results from the first year of combined spectroscopic and photometric observations of the Sloan Digital Sky Survey Reverberation Mapping Project. We successfully recover reverberation time delays between the g+i band emission and the broad H{beta} emission line for a total of 44 quasars, and for the broad H{alpha} emission line in 18 quasars. Time delays are computed using the JAVELIN and CREAM software and the traditional interpolated cross-correlation function (ICCF): using well-defined criteria, we report measurements of 32 H{beta} and 13 H{alpha} lags with JAVELIN, 42 H{beta} and 17 H{alpha} lags with CREAM, and 16 H{beta} and eight H{alpha} lags with the ICCF. Lag values are generally consistent among the three methods, though we typically measure smaller uncertainties with JAVELIN and CREAM than with the ICCF, given the more physically motivated light curve interpolation and more robust statistical modeling of the former two methods. The median redshift of our H{beta}-detected sample of quasars is 0.53, significantly higher than that of the previous reverberation mapping sample. We find that in most objects, the time delay of the H{alpha} emission is consistent with or slightly longer than that of H{beta}. We measure black hole masses using our measured time delays and line widths for these quasars. These black hole mass measurements are mostly consistent with expectations based on the local M_BH_-{sigma}* relationship, and are also consistent with single-epoch black hole mass measurements. This work increases the current sample size of reverberation-mapped active galaxies by about two- thirds and represents the first large sample of reverberation mapping observations beyond the local universe (z<0.3).
1660. SDSS-RM project: H{alpha}, H{beta} & MgII lines
ID:
ivo://CDS.VizieR/J/ApJ/882/4
Title:
SDSS-RM project: H{alpha}, H{beta} & MgII lines
Short Name:
J/ApJ/882/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
The width of the broad emission lines in quasars is commonly characterized by either the FWHM or the square root of the second moment of the line profile ({sigma}line) and used as an indicator of the virial velocity of the broad-line region (BLR) in the estimation of black hole (BH) mass. We measure FWHM and {sigma}line for H{alpha}, H{beta}, and MgII broad lines in both the mean and rms spectra of a large sample of quasars from the Sloan Digital Sky Survey Reverberation Mapping project. We introduce a new quantitative recipe to measure {sigma}line that is reproducible, is less susceptible to noise and blending in the wings, and scales with the intrinsic width of the line. We compare the four definitions of line width (FWHM and {sigma}line in mean and rms spectra, respectively) for each of the three broad lines and among different lines. There are strong correlations among different width definitions for each line, providing justification for using the line width measured in single-epoch spectroscopy as a virial velocity indicator. There are also strong correlations among different lines, suggesting that alternative lines to H{beta} can be used to estimate virial BH masses. We further investigate the correlations between virial BH masses using different line width definitions and the stellar velocity dispersion of the host galaxies and the dependence of line shape (characterized by the ratio FWHM/{sigma}line) on physical properties of the quasar. Our results provide further evidence that FWHM is more sensitive to the orientation of a flattened BLR geometry than {sigma}line, but the overall comparison between the virial BH mass and host stellar velocity dispersion does not provide conclusive evidence that one particular width definition is significantly better than the others.

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