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611. PKS1302-102 intergalactic absorption system
ID:
ivo://CDS.VizieR/J/ApJ/676/262
Title:
PKS1302-102 intergalactic absorption system
Short Name:
J/ApJ/676/262
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed analysis of the intergalactic metal-line absorption systems in the archival HST STIS and FUSE ultraviolet spectra of the low-redshift quasar PKS 1302-102 (z_QSO_=0.2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field.
612. PKS J1209-2032 & CGRaBS J1549+5038 radio spectra
ID:
ivo://CDS.VizieR/J/A+A/643/A174
Title:
PKS J1209-2032 & CGRaBS J1549+5038 radio spectra
Short Name:
J/A+A/643/A174
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of HI 21-cm absorption in a member of the rare and recently discovered class of compact radio sources, "Extremely Inverted Spectrum Extragalactic Radio Sources (EISERS)" . EISERS conceivably form a special sub-class of the inverted spectrum radio galaxies since the spectral index of the optically thick part of the spectrum for these sources crosses the synchrotron self absorption limit of {alpha}=+2.5 (S({nu}) {prop.to} {nu}^{alpha}^). We have searched for HI absorption in two EISERS using the recently upgraded Giant Metrewave Radio Telescope (uGMRT) and detected an absorption feature in one of them. The strong associated HI absorption detected against the source J1209-2032 (z=0.4040) implies an optical depth of 0.178+/-0.02 corresponding to an HI column density of 34.8+/-2.9x10^20^cm^-2^, for an assumed HI spin temperature of 100K and covering factor of 1. This is among the highest known optical depth and HI column densities found for compact radio sources of peaked spectrum type and supports the free-free absorption model for the steeply inverted radio spectrum of this source. For the other source, J1549+5038 (z=2.171), no HI absorption was detected in our observations.
613. PKS 1830-211 OH and HI spectra
ID:
ivo://CDS.VizieR/J/A+A/648/A116
Title:
PKS 1830-211 OH and HI spectra
Short Name:
J/A+A/648/A116
Date:
22 Feb 2022
Publisher:
CDS
Description:
The Large Survey Project (LSP) "MeerKAT Absorption Line Survey" (MALS) is a blind HI 21-cm and OH 18-cm absorption line survey in the L- and UHF-bands, with the primary goal to better determine the occurrence of atomic and molecular gas in the circumgalactic and inter-galactic medium, and its redshift evolution. Here we present the first results using the UHF-band, obtained towards the strongly lensed radio source PKS 1830-211, detecting absorption produced by the lensing galaxy. With merely 90 mins of data acquired on-source for science verification and processed using the Automated Radio Telescope Imaging Pipeline (ARTIP), we detect in absorption the known HI 21-cm and OH 18-cm main lines at z=0.89 at an unprecedented signal-to-noise ratio (4000 in the continuum, in each 6km/s wide channel). For the first time we report the detection at z=0.89 of OH satellite lines, so far not detected at z>0.25. We decompose the OH lines into a thermal and a stimulated contribution, where the 1612 and 1720MHz lines are conjugate. The total OH 1720MHz emission line luminosity is 6100L_{sun}_. This is the most luminous known 1720MHz maser line. It is also among the highest luminosities for the OH-main lines megamasers. The absorption components of the different images of the background source sample different light paths in the lensing galaxy, and their weights in the total absorption spectrum are expected to vary in time, on daily and monthly time scales. We compare our normalized spectra with those obtained more than 20yrs ago, and find no variation, in spite of the high signal-to-noise ratios. We interpret the absorption spectra with the help of a lens galaxy model, derived from an N-body hydro-dynamical simulation, with a morphology similar to its optical HST image. The resulting absorption lines depend mainly on the background continuum, and the radial distribution of the gas surface density, for each atomic /molecular species.We show that it is possible to reproduce the observations assuming a realistic spiral galaxy disk, without invoking any central gas outflows. There are, however, distinct and faint high-velocity features in the ALMA millimeter absorption spectra, that most likely originate from high-velocity clouds or tidal features. These clouds may contribute to broaden the Hi and OH spectra.
614. PKS 1830-211 OH+ and H2O+ spectra
ID:
ivo://CDS.VizieR/J/A+A/595/A128
Title:
PKS 1830-211 OH+ and H2O+ spectra
Short Name:
J/A+A/595/A128
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of OH^+^ and H_2_O^+^ in the z=0.89 absorber toward the lensed quasar PKS 1830-211. The abundance ratio of OH^+^ and H_2_O^+^ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic hydrogen ({dzeta}_H_) along two lines of sight, located at ~2kpc and ~kpc to either side of the absorber's center. The molecular fraction decreases outwards, from ~0.04 to ~0.02, comparable to values measured in the Milky Way at similar galactocentric radii. For {dzeta}_H_, we find values of ~2x10^-14^s^-1^ and ~3x10^-15^s^-1^, respectively, which are slightly higher than in the Milky Way at comparable galactocentric radii, possibly due to a higher average star formation activity in the z=0.89 absorber. The ALMA observations of OH^+^, H_2_O^+^, and other hydrides toward PKS 1830-211 reveal the multi-phase composition of the absorbing gas. Taking the column density ratios along the southwest and northeast lines of sight as a proxy of molecular fraction, we classify the species ArH^+^, OH^+^, H_2_Cl^+^, H_2_O^+^, CH, and HF as tracing gases increasingly more molecular. Incidentally, our data allow us to improve the accuracy of H_2_O^+^ rest frequencies and thus refine the spectroscopic parameters.
615. Planck + X/{gamma} observations of blazars
ID:
ivo://CDS.VizieR/J/A+A/541/A160
Title:
Planck + X/{gamma} observations of blazars
Short Name:
J/A+A/541/A160
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and {gamma}-ray bands, with additional 5GHz flux-density limits to ensure a good probability of a Planck detection. We compare our results to those of a companion paper presenting simultaneous Planck and multi-frequency observations of 104 radio-loud northern active galactic nuclei selected at radio frequencies. While we confirm several previous results, our unique data set allows us to demonstrate that the selection method strongly influences the results, producing biases that cannot be ignored.
616. Polarization in BAL QSOs
ID:
ivo://CDS.VizieR/J/A+A/427/107
Title:
Polarization in BAL QSOs
Short Name:
J/A+A/427/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of several statistical tests performed on a large sample of 139 broad absorption line (BAL) QSOs with good quality optical spectra and/or optical polarization data. Correlations between ten optical indices and the polarization degree p_0_ are systematically searched for.
617. Polarization of broad absorption line QSOs
ID:
ivo://CDS.VizieR/J/ApJ/512/125
Title:
Polarization of broad absorption line QSOs
Short Name:
J/ApJ/512/125
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the combined results of optical polarization surveys of QSOs showing broad absorption lines (BALQSOs) conducted at the Steward and McDonald Observatories. The merged list of 53 objects provides the first statistical justification for claims of the tendency of BALQSOs to show stronger than average polarization, with a typical BALQSO being polarized a factor 2.4 times greater than a QSO from an optical survey selected without regard for absorption lines. Spectropolarimetry of sufficient quality to distinguish the polarization of emission lines versus absorption troughs versus continuum is also presented for six objects from the survey.
618. Polarization of quasars
ID:
ivo://CDS.VizieR/J/A+A/620/A68
Title:
Polarization of quasars
Short Name:
J/A+A/620/A68
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report 87 previously unpublished optical linear polarization measurements of 86 quasars obtained in May and October 2008, and from April to July 2015 with the FOcal Reducer and low-dispersion Spectrographs FORS1 and FORS2 attached to the Very Large Telescope at the Paranal Observatory. Of the 86 quasars, 37 have p>=0.6%, 9 have p>=2%, and 1 has p>=10%.
619. Polarization of quasars
ID:
ivo://CDS.VizieR/J/A+A/606/A101
Title:
Polarization of quasars
Short Name:
J/A+A/606/A101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report 192 previously unpublished optical linear polarization measurements of quasars obtained in April 2003, April 2007, and October 2007 with the European Southern Observatory Faint Object Spectrograph and Camera (EFOSC2) instrument attached to the 3.6m telescope at the La Silla Observatory. Each quasar was observed once. Among the 192 quasars, 89 have a polarization degree p>=0.6%, 18 have p>=2%, and two have p>=10%.
620. Position difference vectors and of the jets
ID:
ivo://CDS.VizieR/J/A+A/651/A64
Title:
Position difference vectors and of the jets
Short Name:
J/A+A/651/A64
Date:
22 Feb 2022
Publisher:
CDS
Description:
We aim to study the relative positions of quasar emission centers at different wavelengths in order to help link the various realizations of the International Celestial Reference System (ICRS), and to unveil systematic uncertainties and individual source behavior at different wavelengths. We based our study on four catalogs representing the ICRS, the ICRF3 positions in the three VLBI bands X, K, and Ka, and the Gaia EDR3 catalog in optical wavelengths. We complemented radio source positions with jet kinematics results from the MOJAVE team, allowing us to obtain jet directions on the sky. A six-parameter deformation model was used to remove systematic uncertainties present in the different catalogs. For a set of 194 objects common to the four catalogs and to the objects whose jet kinematics was studied by the MOJAVE team, we computed the orientation between positions at the different wavelengths and with respect to the directions of the jets. We find that the majority of these objects have their radio-to-optical vector along the jet, with the optical centroid downstream from the radio centroids, and that the K and Ka centroids are preferably upstream in the jet with respect to the X centroid, which is consistent with the paradigm of a simple core-jet model. For a population of multiwavelength positions aligned along the jet, astrometric information can therefore be used to measure the direction of the jet independently of imaging. In addition, we find several sources for which the optical centroid coincides with stationary radio features with a relatively high fraction of polarization, indicating optical emission dominated by a synchrotron process in the jet.