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581. Optical Polarization of 47 QSOs
ID:
ivo://CDS.VizieR/J/A+AS/142/451
Title:
Optical Polarization of 47 QSOs
Short Name:
J/A+AS/142/451
Date:
21 Oct 2021
Publisher:
CDS
Description:
New broad-band linear polarization measurements are presented for a sample of 47 QSOs which includes 27 broad absorption line QSOs and 2 gravitational lens candidates.
582. Optical polarization of 203 QSOs
ID:
ivo://CDS.VizieR/J/A+A/433/757
Title:
Optical polarization of 203 QSOs
Short Name:
J/A+A/433/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
This Table contains linear polarization measurements (mainly in the V band) of 203 QSOs. First time measurements have been obtained for 184 objects. Among them 109 known radio emitters, 42 BAL and 1 gravitationally lensed QSO.
583. Optical positions of ICRF sources
ID:
ivo://CDS.VizieR/J/AJ/125/2728
Title:
Optical positions of ICRF sources
Short Name:
J/AJ/125/2728
Date:
21 Oct 2021
Publisher:
CDS
Description:
New optical positions on the 30mas precision level have been obtained for 172 extragalactic International Celestial Reference Frame (ICRF) sources mainly in the range -30{deg}<=DE<=+25{deg}. Results are presented from a pilot investigation including four Cerro Tololo (CTIO) 0.9m runs (1999-2001). Reference stars in the R~10-16.5mag used. Systematic errors have been investigated, and a field distortion pattern based on the residuals has been removed. The errors of the fainter stars in the CTIO data were assessed by evaluating an auxiliary set of CCD observations of common ICRF sources, taken at the 1.60m Cassegrain telescope of the Laboratorio Nacional de Astrofisica, Brazil. A significant improvement in the optical positions was achieved over a previous determination of source positions. The mean optical positions are compared with the ICRF radio positions. The overall optical minus radio offsets are -6 and -15mas for right ascension and declination, respectively. The formal internal error of these mean offsets is ~2.3mas. his indicates a possible systematic error in the UCAC declinations of 10 to 15mas. Both the optical counterpart observations and the optical reference stars are observed about 9 yr after the Hipparcos mean epoch, and our results set an upper limit for a possible Hipparcos system rotation with respect to the International Celestial Reference System for the z-axis of about 0.7mas/yr.
584. Optical, radio and X-ray properties for 113 QSOs
ID:
ivo://CDS.VizieR/J/ApJ/895/114
Title:
Optical, radio and X-ray properties for 113 QSOs
Short Name:
J/ApJ/895/114
Date:
16 Mar 2022 00:19:12
Publisher:
CDS
Description:
We investigate whether the correlation between the hard X-ray photon index ({Gamma}) and accretion rate for super-Eddington accreting quasars is different from that for sub-Eddington accreting quasars. We construct a sample of 113 bright quasars from the Sloan Digital Sky Survey Data Release 14 quasar catalog, with 38 quasars as the super-Eddington subsample and 75 quasars as the sub-Eddington subsample. We derive black hole masses using a simple-epoch virial mass formula based on the H{beta} lines, and we use the standard thin disk model to derive the dimensionless accretion rates (M) for our sample. The X-ray data for these quasars are collected from the Chandra and XMM-Newton archives. We fit the hard X-ray spectra using a single power-law model to obtain {Gamma} values. We find a statistically significant (R_S_=0.43, p=7.75x10^-3^) correlation between {Gamma} and M for the super-Eddington subsample. The {Gamma}-M correlation for the sub-Eddington subsample is also significant, but weaker (R_S_=0.30, p=9.98x10^-3^). Linear regression analysis shows that {Gamma}=(0.34{+/-}0.11)log(M)+(1.71{+/-}0.17) and {Gamma}=(0.09{+/-}0.04)log(M)+(1.93{+/-}0.04) for the super- and sub-Eddington subsamples, respectively. The {Gamma}-M correlations of the two subsamples are different, suggesting different disk-corona connections in these two types of systems. We propose one qualitative explanation of the steeper {Gamma}-M correlation in the super-Eddington regime that involves larger seed photon fluxes received by the compact coronae from the thick disks in super-Eddington accreting quasars.
585. Optical spectroscopic atlas of low-redshift AGN
ID:
ivo://CDS.VizieR/J/ApJS/145/199
Title:
Optical spectroscopic atlas of low-redshift AGN
Short Name:
J/ApJS/145/199
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a spectral atlas of the H{beta} region for 215 type 1 AGNs (luminous Seyfert 1/radio galaxy nuclei and low-z quasars) up to z~0.8. Line profiles and measures were derived from the database of intermediate resolution spectra (R>~1000) with average continuum level S/N ratio ~30. Parameters including rest frame equivalent width and FWHM are provided for the FeII_opt_ blend at {lambda}4570, H{beta}, HeII {lambda}4686, and the [OIII] {lambda}{lambda}4959, 5007 emission lines. We extract clean broad component H{beta} profiles and provide wavelength measurements at 0, 1/4, 1/2, 3/4, and 0.9 peak intensity levels in order to permit a quantitative definition of the H{beta} broad component for statistical studies. We also discuss sources of uncertainty, selection effects, and biases in our sample. The data are especially important for tests of the eigenvector 1 parameter space occupation and correlation. We show that the I Zw 1 template FeII_opt_ spectrum reproduces well the observed FeII_opt_ emission for a wide range of line width and strength. A detailed analysis of the data within the eigenvector 1 context is deferred to a companion paper.
586. Optical spectroscopic atlas of MOJAVE AGNs
ID:
ivo://CDS.VizieR/J/other/RMxAA/48.9
Title:
Optical spectroscopic atlas of MOJAVE AGNs
Short Name:
J/other/RMxAA/48
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an optical spectroscopic atlas for 123 core-dominated radio-loud active galactic nuclei with relativistic jets, drawn from the MOJAVE/2cm (Monitoring of Jets in AGN with VLBA Experiments) sample at 15GHz. It is the first time that spectroscopic and photometric parameters for a large sample of such type of AGN are presented.
587. Optical spectroscopy of 1LAC broad-line blazars
ID:
ivo://CDS.VizieR/J/ApJ/748/49
Title:
Optical spectroscopy of 1LAC broad-line blazars
Short Name:
J/ApJ/748/49
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on optical spectroscopy of 165 flat spectrum radio quasars (FSRQs) in the Fermi 1LAC sample, which have helped allow a nearly complete study of this population. Fermi FSRQs show significant evidence for non-thermal emission even in the optical; the degree depends on the {gamma}-ray hardness. They also have smaller virial estimates of hole mass than the optical quasar sample. This appears to be largely due to a preferred (axial) view of the {gamma}-ray FSRQ and non-isotropic (H/R ~ 0.4) distribution of broad-line velocities. Even after correction for this bias, the Fermi FSRQs show higher mean Eddington ratios than the optical population. A comparison of optical spectral properties with Owens Valley Radio Observatory radio flare activity shows no strong correlation.
588. Optical spectroscopy of 77 luminous AGNs and QSOs
ID:
ivo://CDS.VizieR/J/AJ/133/186
Title:
Optical spectroscopy of 77 luminous AGNs and QSOs
Short Name:
J/AJ/133/186
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present optical spectroscopy of a sample of 77 luminous active galactic nuclei (AGNs) and quasars selected on the basis of their mid-infrared colors. Our objects are selected from the Spitzer Extragalactic First Look Survey and the SWIRE XMM-Newton Large-Scale Structure Survey (XMM-LSS) fields, with a typical 24um flux density of 5mJy. The median redshift is 0.6, with a range of ~0.05-4. Only 33% (25 out of 77) of these objects are normal type 1 quasars, with no obscuration. Forty-four percent (34 out of 77) are type 2 objects, with high-ionization, narrow emission lines, and 14% (11 out of 77) are dust-reddened type 1 quasars, showing broad lines but a dust-reddened or unusually weak quasar continuum.
589. Optical spectroscopy of radio sources
ID:
ivo://CDS.VizieR/III/175
Title:
Optical spectroscopy of radio sources
Short Name:
III/175
Date:
21 Oct 2021
Publisher:
CDS
Description:
A number of flat spectrum radio sources have been observed in optical spectroscopy; most of the sources are either classified as BL Lacertae objects or have been described as BL Lac candidates.
590. 2001-02 optical variability of blazar 3C 279
ID:
ivo://CDS.VizieR/J/AJ/133/2866
Title:
2001-02 optical variability of blazar 3C 279
Short Name:
J/AJ/133/2866
Date:
21 Oct 2021
Publisher:
CDS
Description:
During 2001-2002 the optically violent variable blazar 3C 279 underwent the most intense outburst seen during the entire 14yr period that this quasar has been studied at Colgate University's Foggy Bottom Observatory. This study concentrates on ~1600 R-filter images taken during this period of activity. This data set includes 29 nights of microvariability coverage. The outburst began in 2001 March, after 3C 279 had faded to its faintest level, R=15.5, in 4yr. The source reached its brightest level, R=12.5, in the 14yr of our study in 2001 August, at which time it became unobservable due to its proximity to the Sun. On becoming observable again in 2001 mid-December, 3C 279 fluctuated between R=13.9 and 14.7, until a dramatic decrease in flux level in 2002 June-July brought the source back down to a level comparable to its preoutburst state. The source exhibited numerous week-long flares of approximately 1mag during the outburst period. Superposed on these flares were night-to-night variations of up to 0.5mag and intranight microvariability of up to 0.13mag in 3hr. We use visual inspection of the light curve, as well as numerical timescale analysis tools (the autocorrelation function, the structure function, and the power spectrum), to characterize the multiple timescales of variability ranging from 1.5yr to several hours.