- ID:
- ivo://CDS.VizieR/J/AJ/126/2579
- Title:
- SDSS quasar catalog. II. First data release
- Short Name:
- J/AJ/126/2579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the second edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog. The catalog consists of the 16,713 objects in the SDSS First Data Release that have luminosities larger than M_i_=-22 (in a cosmology with H_0_=70km/s/Mpc, {Omega}_M_=0.3, and {Omega}_{Lambda}_=0.7), have at least one emission line with FWHM larger than 1000km/s, and have highly reliable redshifts. The area covered by the catalog is 1360{deg}^2^. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.43. For each object, the catalog presents positions accurate to better than 0.2" rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03mag, and information on the morphology and selection method. The catalog also contains some radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. Calibrated digital spectra of all objects in the catalog, covering the wavelength region 3800-9200{AA} at a spectral resolution of 1800-2100, are available. This publication supersedes the first SDSS Quasar Catalog (2002, Cat. <J/AJ/123/567>), which was based on material from the SDSS Early Data Release. A summary of corrections to current quasar databases is also provided. The majority of the objects were found in SDSS commissioning data using a multicolor selection technique. Since the quasar selection algorithm was undergoing testing during the entire observational period covered by this catalog, care must be taken when assembling samples from the catalog for use in statistical studies. A total of 15786 objects (94%) in the catalog were discovered by the SDSS; 12173 of the SDSS discoveries are reported here for the first time. Included in the new discoveries are five quasars brighter than i=16.0 and 17 quasars with redshifts larger than 4.5.
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Search Results
- ID:
- ivo://CDS.VizieR/VII/243
- Title:
- SDSS quasar catalog. III.
- Short Name:
- VII/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog consists of the 46,420 objects in the SDSS Third Data Release that have luminosities larger than M_i_=-22 (in a cosmology with Ho=70km/s/Mpc, {Omega}_M_=0.3 and {Omega}_{Lambda}_=0.7), have at least one emission line with FWHM larger than 1000 km/s or are unambiguously broad absorption line quasars, are fainter than i=15.0 and have highly reliable redshifts. The area covered by the catalog is about 4188 deg^2^. The quasar redshifts range from 0.08 to 5.41, with a median value of 1.47; the high-redshift sample includes 520 quasars at redshifts greater than four, of which 17 are at redshifts greater than five. For each object the catalog presents positions accurate to better than 0.2" rms per coordinate, five-band (ugriz) CCD-based photometry with typical accuracy of 0.03 mag, and information on the morphology and selection method. The catalog also contains radio, near-infrared, and X-ray emission properties of the quasars, when available, from other large-area surveys. The calibrated digital spectra cover the wavelength region 3800-9200{AA} at a spectral resolution of about 2000; the spectra can be retrieved from the public database using the information provided in the catalog. A total of 44,221 objects in the catalog were discovered by the SDSS; 28,400 of the SDSS discoveries are reported here for the first time.
- ID:
- ivo://CDS.VizieR/J/ApJS/201/10
- Title:
- SDSS quasar catalog with Swift observations
- Short Name:
- J/ApJS/201/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a catalog of optically selected quasars with simultaneous observations in UV/optical and X-ray bands by the Swift Gamma-ray Burst Explorer. Objects in this catalog are identified by matching the Swift pointings with the Sloan Digital Sky Survey Data Release 5 quasar catalog. The final catalog contains 843 objects, among which 637 have both Ultraviolet Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations and 354 of which are detected by both instruments. The overall X-ray detection rate is ~60% which rises to ~85% among sources with at least 10ks of XRT exposure time. We construct the time-averaged spectral energy distribution (SED) for each of the 354 quasars using UVOT photometric measurements and XRT spectra. From model fits to these SEDs, we find that the big blue bump contributes about ~0.3 dex to the quasar luminosity. We re-visit the {alpha}_ox_-L_2500_{AA} relation by selecting a clean sample with only Type 1 radio-quiet quasars; the dispersion of this relation is reduced by at least 15% compared with studies that use non-simultaneous UV/optical and X-ray data.
- ID:
- ivo://CDS.VizieR/J/AJ/135/496
- Title:
- SDSS quasar lens search. II.
- Short Name:
- J/AJ/135/496
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46420 quasars from the SDSS Data Release 3 (~4188deg^2^), we select a subsample of 22683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction-corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1" and 20" and flux ratios of faint to bright lensed images larger than 10^-0.5^. We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations (~1"-2") and one is a large separation (15") system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample.
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/60
- Title:
- SDSS RGB stars distances
- Short Name:
- J/ApJ/794/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present distance determinations for a large and clean sample of red giant branch stars selected from the ninth data release of the Sloan Digital Sky Survey (Adelman-McCarthy et al. 2012ApJS..203...21A, Cat. V/139). The distances are calculated based on both observational cluster fiducials and theoretical isochrones. Distributions of distances from the two methods are very similar with peaks at about 10 kpc and tails extending to more than 70 kpc. We find that distances from the two methods agree well for the majority of the sample stars; though, on average, distances based on isochrones are 10% higher than those based on fiducials. We test the accuracy of our distance determinations using 332 stars from 10 Galactic globular and open clusters. The average relative deviation from the literature cluster distances is 4% for the fiducial-based distances and 8% for the isochrone-based distances, both of which are within the uncertainties. We find that the effective temperature and surface gravity derived from low-resolution spectra are not accurate enough to essentially improve the performance of distance determinations. However, for stars with significant extinction, effective temperature may help to better constrain their distances to some extent. We make our sample stars and their distances available from an online catalog. The catalog comprises 17941 stars with reasonable distance estimations reaching to more than 70 kpc, which is suitable for the investigation of the formation and evolution of the Galaxy, especially the Galactic halo.
- 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.
- 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).
- ID:
- ivo://CDS.VizieR/J/ApJ/901/55
- Title:
- SDSS-RM project: MgII lags from 4yrs monitoring
- Short Name:
- J/ApJ/901/55
- Date:
- 17 Feb 2022 11:27:58
- Publisher:
- CDS
- Description:
- We present reverberation mapping results for the MgII{lambda}2800{AA} broad emission line in a sample of 193 quasars at 0.35<z<1.7 with photometric and spectroscopic monitoring observations from the Sloan Digital Sky Survey Reverberation Mapping project during 2014-2017. We find significant time lags between the MgII and continuum lightcurves for 57 quasars, and define a "gold sample" of 24 quasars with the most reliable lag measurements. We estimate false-positive rates for each lag that range from 1% to 24%, with an average false-positive rate of 11% for the full sample and 8% for the gold sample. There are an additional ~40 quasars with marginal MgII lag detections, which may yield reliable lags after additional years of monitoring. The MgII lags follow a radius-luminosity relation with a best-fit slope that is consistent with {alpha}=0.5, but with an intrinsic scatter of 0.36dex that is significantly larger than found for the H{beta} radius-luminosity relation. For targets with SDSS-RM lag measurements of other emission lines, we find that our MgII lags are similar to the H{beta} lags and ~2-3 times larger than the CIV lags. This work significantly increases the number of MgII broad-line lags and provides additional reverberation-mapped black hole masses, filling the redshift gap at the peak of supermassive black hole growth between the H{beta} and CIV emission lines in optical spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/4
- Title:
- SDSS-RM project: technical overview
- Short Name:
- J/ApJS/216/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project is a dedicated multi-object RM experiment that has spectroscopically monitored a sample of 849 broad-line quasars in a single 7deg^2^ field with the SDSS-III Baryon Oscillation Spectroscopic Survey spectrograph. The RM quasar sample is flux-limited to i_psf_=21.7mag, and covers a redshift range of 0.1<z<4.5 without any other cuts on quasar properties. Optical spectroscopy was performed during 2014 January-July dark/gray time, with an average cadence of ~4 days, totaling more than 30 epochs. Supporting photometric monitoring in the g and i bands was conducted at multiple facilities including the Canada-France-Hawaii Telescope (CFHT) and the Steward Observatory Bok telescope in 2014, with a cadence of ~2 days and covering all lunar phases. The RM field (RAJ2000=14:14:49.00, DEJ2000=+53:05:00.0) lies within the CFHT-LS W3 field, and coincides with the Pan-STARRS 1 (PS1) Medium Deep Field MD07, with three prior years of multi-band PS1 light curves. The SDSS-RM six month baseline program aims to detect time lags between the quasar continuum and broad line region (BLR) variability on timescales of up to several months (in the observed frame) for ~10% of the sample, and to anchor the time baseline for continued monitoring in the future to detect lags on longer timescales and at higher redshift. SDSS-RM is the first major program to systematically explore the potential of RM for broad-line quasars at z>0.3, and will investigate the prospects of RM with all major broad lines covered in optical spectroscopy.
