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Start Over Subject quasars Content Level Research
941. The multi-component absorber QSO 0318-0600
ID:
ivo://CDS.VizieR/J/ApJ/709/611
Title:
The multi-component absorber QSO 0318-0600
Short Name:
J/ApJ/709/611
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present high spectral resolution Very Large Telescope observations of the broad absorption line quasar SDSS J0318-0600. This high-quality data set allows us to extract accurate ionic column densities and determine an electron number density of n_e_=10^3.3+/-0.2^cm^-3^ for the main outflow absorption component. The heavily reddened spectrum of SDSS J0318-0600 requires purely silicate dust with a reddening curve characteristic of predominately large grains, from which we estimate the bolometric luminosity. We carry out photoionization modeling to determine the total column density, ionization parameter, and distance of the gas and find that the photoionization models suggest abundances greater than solar. Due to the uncertainty in the location of the dust extinction, we arrive at two viable distances for the main ouflow component from the central source, 6 and 17kpc, where we consider the 6kpc location as somewhat more physically plausible. Assuming the canonical global covering of 20% for the outflow and a distance of 6kpc, our analysis yields a mass flux of 120M_{sun}_/yr and a kinetic luminosity that is ~0.1% of the bolometric luminosity of the object. Should the dust be part of the outflow, then these values are ~4x larger. The large mass flux and kinetic luminosity make this outflow a significant contributor to active galactic nucleus feedback processes.
942. The MWA view of Fermi blazars
ID:
ivo://CDS.VizieR/J/A+A/588/A141
Title:
The MWA view of Fermi blazars
Short Name:
J/A+A/588/A141
Date:
21 Oct 2021
Publisher:
CDS
Description:
Low-frequency radio arrays are opening a new window for the study of the sky, both to study new phenomena and to better characterize known source classes. Being flat-spectrum sources, blazars are so far poorly studied at low radio frequencies. We characterize the spectral properties of the blazar population at low radio frequency, compare the radio and high-energy properties of the gamma-ray blazar population, and search for radio counterparts of unidentified gamma-ray sources. We cross-correlated the 6100-deg^2^ Murchison Widefield Array Commissioning Survey catalogue with the Roma blazar catalogue, the third catalogue of active galactic nuclei detected by Fermi-LAT, and the unidentified members of the entire third catalogue of gamma-ray sources detected by Fermi-LAT. When available, we also added high-frequency radio data from the Australia Telescope 20GHz catalogue.
943. The [OIII] emission line in SDSS AGNs
ID:
ivo://CDS.VizieR/J/ApJ/737/71
Title:
The [OIII] emission line in SDSS AGNs
Short Name:
J/ApJ/737/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the equivalent width (EW) of the [OIII]{lambda}5007 emission line, and their correlations with physical parameters of active galactic nuclei (AGNs). We find a significant and negative correlation between the EW of the core component, EW(core), and the blueshift of either the core (the peak), the wing, or the total profile of [OIII] emission; it is fairly strong for the blueshift of the total profile in particular. However, both quantities (EW and velocity shift) generally have only weak, if any, correlations with fundamental AGN parameters such as the nuclear continuum luminosity at 5100{AA} (L_5100_), black hole mass (M_BH_), and the Eddington ratio (L/L_Edd_); these correlations include the classical Baldwin effect of EW(core), an inverse Baldwin effect of EW(wing), and the relationship between velocity shifts and L/L_Edd_. Our findings suggest that both the large object-to-object variation in the strength of [OIII] emission and the blueshift-EW(core) connection are not governed primarily by fundamental AGN parameters such as L_5100_, M_BH_, and L/L_Edd_. We propose that the interstellar medium conditions of the host galaxies play a major role instead in the diversity of the [OIII] properties in active galaxies. This suggests that the use of [OIII]{lambda}5007 luminosity as a proxy of AGN luminosity does not depend strongly on the above-mentioned fundamental AGN parameters.
944. The Parkes quarter-Jansky flat-spectrum sample
ID:
ivo://CDS.VizieR/J/A+A/386/97
Title:
The Parkes quarter-Jansky flat-spectrum sample
Short Name:
J/A+A/386/97
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new sample of quarter-Jansky flat-spectrum radio sources selected to search for high-redshift quasars and to study the evolution of the flat-spectrum quasar population. The sample comprises 878 radio sources selected from the Parkes catalogues with spectral indices {alpha}^5GHz^_2.7GHz_>=-0.4 where S_{nu}{prop.to}{nu}^{alpha}. The sample covers all right ascensions and the declination range from -80.0{deg} to +2.5{deg}, excluding low galactic latitudes (|b|<10{deg}) and the Magellanic Cloud regions. We have obtained improved radio source positions, firstly to reconfirm the majority of the existing identifications, and secondly, using digitized sky-survey data and deep B, Gunn-i and Gunn-z CCD-imaging, to find optical identifications for 223 previously-unidentified sources. We present the final catalogue of 878 flat-spectrum sources: 827 are compact radio sources identified with galaxies, quasars and BL Lac objects, 38 have either extended radio structure or are identified with Galactic objects (PN, HII or non-compact radio source), 4 are obscured by Galactic stars, and 9 (1 per cent of the total sample) remain unidentified.
945. The quasars MMT-BOSS pilot survey
ID:
ivo://CDS.VizieR/J/ApJS/199/3
Title:
The quasars MMT-BOSS pilot survey
Short Name:
J/ApJS/199/3
Date:
21 Oct 2021
Publisher:
CDS
Description:
The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10000deg^2^, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations (BAOs) in the distribution of Ly{alpha} absorption from the spectra of a sample of ~150000 z>2.2 quasars. Along with measuring the angular diameter distance at z~2.5, BOSS will provide the first direct measurement of the expansion rate of the universe at z>2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars in the redshift range 2.2<z<3.5, where their colors tend to overlap those of the far more numerous stars. During the first year of the BOSS survey, quasar target selection (QTS) methods were developed and tested to meet the requirement of delivering at least 15 quasars/deg^2^ in this redshift range, with a goal of 20 out of 40 targets/deg^2^ allocated to the quasar survey. To achieve these surface densities, the magnitude limit of the quasar targets was set at g<=22.0 or r<=21.85. We have defined a uniformly selected subsample of 20 targets/deg^2^, for which the selection efficiency is just over 50% (~10 z>2.20 quasars/deg^2^). This "CORE" subsample will be fixed for Years Two through Five of the survey. In this paper, we describe the evolution and implementation of the BOSS QTS algorithms during the first two years of BOSS operations (through 2011 July), in support of the science investigations based on these data, and we analyze the spectra obtained during the first year. During this year, 11263 new z>2.20 quasars were spectroscopically confirmed by BOSS, roughly double the number of previously known quasars with z>2.20. Our current algorithms select an average of 15 z>2.20 quasars/deg^2^ from 40 targets/deg^2^ using single-epoch SDSS imaging.
946. The Roma BZCAT - 5th edition
ID:
ivo://CDS.VizieR/VII/274
Title:
The Roma BZCAT - 5th edition
Short Name:
VII/274
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Roma-BZCAT is now at the 5th Edition which contains coordinates and multi-frequency data of 3561 sources, about 30% more than in the 1st edition, either confirmed blazars or exhibiting characteristics close to this type of sources. With respect to the previous editions, this new edition has relevant changes in the sources' classification and has a new format for the notes in the tables. We emphasize that all the sources in the Roma-BZCAT have a detection in the radio band. Moreover, a complete spectroscopic information is published and could be accessed by us for all of them, with the exception of BL Lac candidates. Consequently, peculiar sources as the so called "radio quiet BL Lacs", which are reported in some other catalogues, are not included here because of possible contamination with hot stars and other extragalactic objects.
947. The SDSS-DR3 damped Ly{alpha} survey
ID:
ivo://CDS.VizieR/J/ApJ/635/123
Title:
The SDSS-DR3 damped Ly{alpha} survey
Short Name:
J/ApJ/635/123
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results from a damped Ly{alpha} survey of the Sloan Digital Sky Survey, Data Release 3 (Cat. <II/259>). We have discovered over 500 new damped Ly{alpha} systems at z>2.2, and the complete statistical sample for z>1.6 has more than 600 damped Ly{alpha} galaxies.
948. The SDSS-DR7 quasar catalog
ID:
ivo://CDS.VizieR/VII/260
Title:
The SDSS-DR7 quasar catalog
Short Name:
VII/260
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the fifth edition of the Sloan Digital Sky Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh Data Release. The catalog, which contains 105783 spectroscopically confirmed quasars, represents the conclusion of the SDSS-I and SDSS-II quasar survey. The catalog consists of the SDSS objects that have luminosities larger than M_i_=-22.0 (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 or have interesting/complex absorption features, are fainter than i~15.0, and have highly reliable redshifts. The catalog covers an area of ~9380deg^2^. The quasar redshifts range from 0.065 to 5.46, with a median value of 1.49; the catalog includes 1248 quasars at redshifts greater than 4, of which 56 are at redshifts greater than 5. The catalog contains 9210 quasars with i<18; slightly over half of the entries have i<19. For each object the catalog presents positions accurate to better than 0.1"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 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 ~2000; the spectra can be retrieved from the SDSS public database using the information provided in the catalog. Over 96% of the objects in the catalog were discovered by the SDSS. We also include a supplemental list of an additional 207 quasars with SDSS spectra whose archive photometric information is incomplete.
949. The SDSS DR5/XMM-Newton quasar survey
ID:
ivo://CDS.VizieR/J/ApJS/183/17
Title:
The SDSS DR5/XMM-Newton quasar survey
Short Name:
J/ApJS/183/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 792 Fifth Data Release Sloan Digital Sky Survey quasars with optical spectra that have been observed serendipitously in the X-rays with the XMM-Newton. These quasars cover a redshift range of z=0.11-5.41 and a magnitude range of i=15.3-20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at >=2{sigma} account for 87% of the sample (685 quasars), and 473 quasars are detected at >=6{sigma}, sufficient to allow X-ray spectral fits. For detected sources, ~60% have X-ray fluxes between F_2-10keV_=(1-10)x10^-14^erg/cm^2^/s. We fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio >=6, resulting in a weighted mean photon index {Gamma}=1.91+/-0.08, with an intrinsic dispersion {sigma}_{Gamma}_=0.38.
950. The SDSS Reverberation Mapping (SDSS-RM) project
ID:
ivo://CDS.VizieR/J/ApJS/241/34
Title:
The SDSS Reverberation Mapping (SDSS-RM) project
Short Name:
J/ApJS/241/34
Date:
07 Mar 2022 07:38:42
Publisher:
CDS
Description:
We present a detailed characterization of the 849 broad-line quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. Our quasar sample covers a redshift range of 0.1<z<4.5 and is flux-limited to i_PSF_<21.7 without any other cuts on quasar properties. The main sample characterization includes: (1) spectral measurements of the continuum and broad emission lines for individual objects from the coadded first-season spectroscopy in 2014, (2) identification of broad and narrow absorption lines in the spectra, and (3) optical variability properties for continuum and broad lines from multi-epoch spectroscopy. We provide improved systemic redshift estimates for all quasars and demonstrate the effects of the signal-to-noise ratio on the spectral measurements. We compile measured properties for all 849 quasars along with supplemental multi-wavelength data for subsets of our sample from other surveys. The SDSS-RM sample probes a diverse range in quasar properties and shows well-detected continuum and broad-line variability for many objects from first-season monitoring data. The compiled properties serve as the benchmark for follow-up work based on SDSS-RM data.