- ID:
- ivo://CDS.VizieR/J/A+A/574/A108
- Title:
- Molecular absorption lines in PKS 1830-211
- Short Name:
- J/A+A/574/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on measurements with the Effelsberg 100-m telescope, a multiline study of molecular species is presented toward the southwestern source of the gravitational lens system PKS 1830-211, which is by far the best known target for studying molecular gas in absorption at intermediate redshift. Determining line parameters and optical depths and performing large velocity gradient radiative transfer calculations, the aims of this study are (1) to evaluate physical parameters of the absorbing foreground gas at z~0.89, in particular its homogeneity, and (2) to monitor the spectroscopic time variability caused by fluctuations in the z~2.5 background continuum source.
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- ID:
- ivo://CDS.VizieR/J/AJ/111/645
- Title:
- Morphology of Quasars
- Short Name:
- J/AJ/111/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The optical morphology of bright extragalactic objects listed by Green et al. (1986ApJS...61..305G) is determined on Palomar Observatory Sky Survey prints. Morphological types are assigned according to whether objects appear resolved or unresolved. These are plotted in the Hubble Diagram. When combined with previous results from the Medium-Bright Quasar Survey (MBQS), objects of redshift z are found to be unresolved on 1.2m Schmidt telescopes at apparent magnitudes brighter than B=21-3/4z over a large magnitude range 12.5<B<18.5. A luminosity cutoff for unresolved objects in this range is found to be M_B=-24, (H0=50), in agreement with an earlier estimate. Relevance to the search for large, bright, host galaxies, and for "naked quasar" candidates, is noted.
- ID:
- ivo://CDS.VizieR/J/ApJ/775/92
- Title:
- MQS III: AGNs behind LMC and SMC
- Short Name:
- J/ApJ/775/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Magellanic Quasars Survey (MQS) has now increased the number of quasars known behind the Magellanic Clouds by almost an order of magnitude. All survey fields in the Large Magellanic Cloud (LMC) and 70% of those in the Small Magellanic Cloud (SMC) have been observed. The targets were selected from the third phase of the Optical Gravitational Lensing Experiment (OGLE-III) based on their optical variability, mid-IR, and/or X-ray properties. We spectroscopically confirmed 758 quasars (565 in the LMC and 193 in the SMC) behind the clouds, of which 94% (527 in the LMC and 186 in the SMC) are newly identified. The MQS quasars have long-term (12yr and growing for OGLE), high-cadence light curves, enabling unprecedented variability studies of quasars. The MQS quasars also provide a dense reference grid for measuring both the internal and bulk proper motions of the clouds, and 50 quasars are bright enough (I<~18mag) for absorption studies of the interstellar/intergalactic medium of the clouds.
- ID:
- ivo://CDS.VizieR/J/A+A/495/691
- Title:
- Multifrequency catalogue of blazars, Roma-BZCAT
- Short Name:
- J/A+A/495/691
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalogue of blazars based on multifrequency surveys and on an extensive review of the literature. Blazars are classified as BL Lacertae objects, as flat spectrum radio quasars or as blazars of uncertain/transitional type. Each object is identified by a root name, coded as BZB, BZQ and BZU for these three subclasses respectively, and by its coordinates. This catalogue is being built as a tool useful for the identification of the extragalactic sources that will be detected by present and future experiments for X and gamma-ray astronomy, like Swift, AGILE, Fermi-GLAST and Simbol-X. An electronic version is available from the ASI Science Data Center web site at http://www.asdc.asi.it/bzcat.
- ID:
- ivo://CDS.VizieR/J/PASJ/60/161
- Title:
- Multi-wave band emission from blazars
- Short Name:
- J/PASJ/60/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We studied the correlations of the flux of the broad-line emission (FBLR) with the X-ray emission flux, optical emission flux at 5500{AA} and radio emission flux at 5GHz, respectively, for a large sample of 50 blazars (39 flat-spectrum radio quasars (FSRQs) and 11 BL Lac objects).
- ID:
- ivo://CDS.VizieR/J/A+A/644/A15
- Title:
- MUSE data for MR 2251-178 and PG 1126-041
- Short Name:
- J/A+A/644/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use MUSE adaptive optics (AO) data in Narrow Field Mode to study the properties of the ionised gas in MR 2251-178 and PG 1126-041, two nearby (z~0.06) bright quasars hosting sub-pc scale Ultra Fast Outflows (UFOs) detected in the X-ray band. We decompose the optical emission from diffuse gas into a low- and a high-velocity components. The former is characterised by a clean, regular velocity field and a low (~80 km/s) velocity dispersion. It traces regularly rotating gas in PG 1126-041, while in MR 2251-178 it is possibly associated to tidal debris from a recent merger or flyby. The other component is found to be extended up to a few kpc from the nuclei, and shows a high (~800km/s) velocity dispersion and a blue-shifted mean velocity, as expected from AGN-driven outflows. We estimate mass outflow rates up to a few Mo/yr and kinetic efficiencies between 0.1-0.4 per cent, in line with those of galaxies hosting AGNs of similar luminosity. The momentum rates of these ionised outflows are comparable to those measured for the UFOs at sub-pc scales, consistent with a momentum-driven wind propagation. Pure energy-driven winds are excluded unless about 100x additional momentum is locked in massive molecular winds. By comparing the outflow properties of our sources with those of a small sample of well-studied QSOs hosting UFOs from the literature, we find that winds seem to systematically lie either in a momentum-driven or in an energy-driven regime, indicating that these two theoretical models bracket very well the physics of AGN-driven winds.
- ID:
- ivo://CDS.VizieR/J/A+A/424/519
- Title:
- Naked active galactic nuclei
- Short Name:
- J/A+A/424/519
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report the discovery of a new class of active galactic nucleus in which although the nucleus is viewed directly, no broad emission lines are present. The results are based on a survey for AGN in which a sample of about 800 quasars and emission line galaxies were monitored yearly for 25 years. Among the emission line galaxies was the expected population of Seyfert 2 galaxies with only narrow forbidden lines in emission, and no broad lines. However, from the long term monitoring programme it was clear that some 10% of these were strongly variable with strong continuum emission. It is argued that these objects can only be Seyfert 1 galaxies in which the nucleus is viewed directly, but in which broad emission lines are completely absent. We compare these observations with other cases from the literature where the broad line region is reported to be weak or variable, and investigate the possibility that the absence of the broad line component is due to reddening. We conclude that this does not account for the observations, and that in these AGN the broad line region is absent. We also tentatively identify more luminous quasars from our sample where the broad emission lines also appear to be absent. The consequences of this for AGN models are discussed, and a case is made that we are seeing AGN in a transition stage between the fuel supply from a surrounding star cluster being cut off, and the nucleus becoming dormant.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/128
- Title:
- Narrow line Seyfert 1 galaxies from SDSS-DR3
- Short Name:
- J/ApJS/166/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a systematic search for narrow line Seyfert 1 galaxies (NLS1s) from objects assigned as "QSOs" or "galaxies" in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 3 (SDSS DR3) by a careful modeling of their emission lines and continua. The result is a uniform sample comprising ~2000 NLS1s. This sample dramatically increases the number of known NLS1s by a factor of ~10 over previous compilations. This paper presents the parameters of the prominent emission lines and continua, which were measured accurately with typical uncertainties <10%. Taking advantage of such an unprecedented large and uniform sample with accurately measured spectral parameters, we carried out various statistical analyses, some of which were only possible for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1948
- Title:
- Narrow line Seyfert 1 galaxies in the FBQS
- Short Name:
- J/AJ/131/1948
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 (NLS1) galaxies. These objects are a subset of the First Bright Quasar Survey (Cat. <J/AJ/112/407>) and were initially detected at 20cm (flux density limit 1Jy) in the VLA FIRST Survey.
- ID:
- ivo://CDS.VizieR/J/ApJS/221/32
- Title:
- Narrow MgII absorption lines from SDSS-DR9Q
- Short Name:
- J/ApJS/221/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Data Release 9 Quasar spectra from the Baryonic Oscillation Spectroscopic Survey, which does not include quasar spectra from the Sloan Digital Sky Survey Data Release 7, we detect narrow MgII{lambda}{lambda}2796,2803 absorption doublets in the spectral data redward of 1250{AA} (quasar rest frame) until the red wing of the MgII{lambda}2800 emission line. Our survey is limited to quasar spectra with a median signal-to-noise ratio <S/N>{>=}4/pixel in the surveyed spectral region, resulting in a sample that contains 43260 quasars. We have detected a total of 18598 MgII absorption doublets with 0.2933<=z_abs_<=2.6529. About 75% of absorbers have an equivalent width at rest frame of W_r_^{lambda}2796^. About 75% of absorbers have doublet ratios (DR=W_r_^{lambda}2796^/W_r_^{lambda}2803^) in the range of 1<=DR<=2, and about 3.2% lie outside the range of 1-{sigma}_DR_<=DR<=2+{sigma}_DR_. We characterize the detection false positives/negatives by the frequency of detected MgII absorption doublets in the limits of the S/N of the spectral data. The S/N=4.5 limit is assigned a completeness fraction of 53% and tends to be complete when the S/N is greater than 4.5. The redshift number densities of all of the detected MgII absorbers moderately increase from z~0.4 to z~1.5, which parallels the evolution of the cosmic star formation rate density. Limiting our investigation to those quasars whose emission redshift can be determined from narrow emission lines, the relative velocities ({beta}) of MgII absorbers have a complex distribution which probably consists of three classes of MgII absorbers: (1) cosmologically intervening absorbers; (2) environmental absorbers that reside within the quasar host galaxies or galaxy clusters; (3) quasar outflow absorbers. After subtracting contributions from cosmologically intervening absorbers and environmental absorbers, the {beta} distribution of the MgII might mainly be contributed by the quasar outflow absorbers and peaks at {upsilon}~1500km/s. This peak velocity is lower than the value of 2000km/s found in statistical analysis of CIV absorbers.
