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Start Over Subject quasars Content Level Research
661. QSOs SED shapes from optical to NIR
ID:
ivo://CDS.VizieR/J/MNRAS/434/3104
Title:
QSOs SED shapes from optical to NIR
Short Name:
J/MNRAS/434/3104
Date:
21 Oct 2021
Publisher:
CDS
Description:
We define a quasar-galaxy mixing diagram using the slopes of their spectral energy distributions (SEDs) from 1{mu}m to 3000{AA} and from 1 to 3{mu}m in the rest frame. The mixing diagram can easily distinguish among quasar-dominated, galaxy-dominated and reddening-dominated SED shapes. By studying the position of the 413 XMM-selected type 1 AGN in the wide-field 'Cosmic Evolution Survey' in the mixing diagram, we find that a combination of the Elvis et al. (2012ApJ...759....6E, Cat. J/ApJ/759/6) mean quasar SED with various contributions from galaxy emission and some dust reddening is remarkably effective in describing the SED shape from 0.3 to 3{mu}m for large ranges of redshift, luminosity, black hole mass and Eddington ratio of type 1 AGN. In particular, the location in the mixing diagram of the highest luminosity AGN is very close (within 1{sigma}) to that of the Elvis et al. (2012ApJ...759....6E, Cat. J/ApJ/759/6) SED template. The mixing diagram can also be used to estimate the host galaxy fraction and reddening in quasar. We also show examples of some outliers which might be AGN in different evolutionary stages compared to the majority of AGN in the quasar-host galaxy co-evolution cycle.
662. QSOs selection from SDSS and WISE
ID:
ivo://CDS.VizieR/J/ApJS/219/39
Title:
QSOs selection from SDSS and WISE
Short Name:
J/ApJS/219/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
We identify 885503 type 1 quasar candidates to i<~22 using the combination of optical and mid-IR photometry. Optical photometry is taken from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III/BOSS), while mid-IR photometry comes from a combination of data from the Wide-field Infrared Survey Explorer (WISE) "AllWISE" data release and several large-area Spitzer Space Telescope fields. Selection is based on a Bayesian kernel density algorithm with a training sample of 157701 spectroscopically confirmed type 1 quasars with both optical and mid-IR data. Of the quasar candidates, 733713 lack spectroscopic confirmation (and 305623 are objects that we have not previously classified as photometric quasar candidates). These candidates include 7874 objects targeted as high-probability potential quasars with 3.5<z<5 (of which 6779 are new photometric candidates). Our algorithm is more complete to z>3.5 than the traditional mid-IR selection "wedges" and to 2.2<z<3.5 quasars than the SDSS-III/BOSS project. Number counts and luminosity function analysis suggest that the resulting catalog is relatively complete to known quasars and is identifying new high-z quasars at z>3. This catalog paves the way for luminosity-dependent clustering investigations of large numbers of faint, high-redshift quasars and for further machine-learning quasar selection using Spitzer and WISE data combined with other large-area optical imaging surveys.
663. 2 QSOs SINFONI K-band datacubes
ID:
ivo://CDS.VizieR/J/A+A/591/A28
Title:
2 QSOs SINFONI K-band datacubes
Short Name:
J/A+A/591/A28
Date:
21 Oct 2021
Publisher:
CDS
Description:
Negative feedback from active galactic nuclei (AGN) is considered a key mechanism in shaping galaxy evolution. Fast, extended outflows are frequently detected in the AGN host galaxies at all redshifts and luminosities, both in ionised and molecular gas. However, these outflows are only potentially able to quench star formation, and we are still lacking decisive evidence of negative feedback in action. Here we present observations obtained with the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) H- and K-band integral-field of two quasars at z~2.4 that are characterised by fast, extended outflows detected through the [OIII]{lambda}5007 line. The high signal-to-noise ratio of our observations allows us to identify faint narrow (FWHM<500km/s) and spatially extended components in [OIII]{lambda}5007 and H{alpha} emission associated with star formation in the host galaxy. This star formation powered emission is spatially anti-correlated with the fast outflows. The ionised outflows therefore appear to be able to suppress star formation in the region where the outflow is expanding. However, the detection of narrow spatially extended H{alpha}emission indicates star formation rates of at least ~50-90M_{sun}/yr, suggesting either that AGN feedback does not affect the whole galaxy or that many feedback episodes are required before star formation is completely quenched. On the other hand, the narrow H{alpha} emission extending along the edges of the outflow cone may also lead also to a positive feedback interpretation. Our results highlight the possible double role of galaxy-wide outflows in host galaxy evolution.
664. QSO Type1/Type2 dichotomy
ID:
ivo://CDS.VizieR/J/A+A/478/321
Title:
QSO Type1/Type2 dichotomy
Short Name:
J/A+A/478/321
Date:
21 Oct 2021
Publisher:
CDS
Description:
For Seyfert galaxies, the AGN unification model provides a simple and well-established explanation of the type 1/type 2 dichotomy through orientation-based effects. The generalization of this unification model to the higher luminosity AGNs that quasars are remains a key question. The recent detection of type 2 radio-quiet quasars seems to support such an extension. We propose a further test of this scenario. On the basis of a compilation of quasar host-galaxy position angles consisting of previously published data and of new measurements performed using HST Archive images, we investigate the possible existence of a correlation between the linear polarization position angle and the host-galaxy/extended emission position angle of quasars.
665. QSO type 2 VLA images
ID:
ivo://CDS.VizieR/J/A+A/650/A84
Title:
QSO type 2 VLA images
Short Name:
J/A+A/650/A84
Date:
22 Feb 2022
Publisher:
CDS
Description:
The role of radio mode feedback in non radio-loud quasars needs to be explored in depth to determine its true importance. Its effects can be identified based on the evidence of interactions between the radio structures and the ambient ionised gas. We investigate this in a sample of 13 optically selected type-2 quasars (QSO2) at z<0.2 with Very Large Array (VLA) FIRST Survey radio detections. None are radio loud. The ranges of [OIII]c1l{lambda}5007 and monochromatic radio luminosities are log(L[OIII]=erg/s)~42.08-42.79 and log(P_1.4GHz_/erg/s/Hz)~30.08-31.76. All show complex optical morphologies, with signs of distortion across tens of kpc due to mergers/interactions. We have searched for evidence of interactions between the radio structures and the ionised gas by characterising and comparing their morphologies. The first is traced by narrow band H images obtained with the GTC 10.4m Spanish telescope and the Osiris instrument. The second is traced by VLA radio maps obtained with A and B configurations to achieve both high resolution and brightness sensitivity. The radio luminosity has an active galatic nucleus (AGN) component in 11/13 QSO2, which is spatially extended in our radio data in 9 of them (jets/lobes/other). The relative contribution of the extended radio emission to the total P_1.4GHz_ is in most cases in the range 30% to 90%. The maximum sizes are in the range d^R^_max_~few-500kpc. QSO2 undergoing interaction/merger events appear to be invariably associated with ionised gas spread over large spatial scales with maximum distances from the AGN in the range rmax~12-90kpc. The morphology of the ionised gas at <30kpc is strongly influenced by AGN related processes. Evidence for radio-gas interactions exist in 10/13 QSO2; that is, all but one with confirmed AGN radio components. The interactions are identified across different spatial scales, from the nuclear narrow line region up to tens of kpc. Although this sample cannot be considered representative of the general population of QSO2, it supports the idea that large scale low/modest power radio sources can exist in radio-quiet QSO2, which can provide a source of feedback on scales of the spheroidal component of galaxies and well into the circumgalactic medium, in systems where radiative mode feedback is expected to dominate.
666. Quadruply lensed quasar WFI2033-4723 light curves
ID:
ivo://CDS.VizieR/J/A+A/629/A97
Title:
Quadruply lensed quasar WFI2033-4723 light curves
Short Name:
J/A+A/629/A97
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new measurements of the time delays of WFI2033-4723. The data sets used in this work include 14 years of data taken at the 1.2m Leonhard Euler Swiss telescope, 13 years of data from the SMARTS 1.3m telescope at Las Campanas Observatory and a single year of high-cadence and high-precision monitoring at the MPIA 2.2m telescope. The time delays measured from these different data sets, all taken in the R-band, are in good agreement with each other and with previous measurements from the literature. Combining all the time-delay estimates from our data sets results in Dt_AB_=36.2_-0.8_^+0.7^days (2.1% precision), Dt_AC_=-23.3_-1.4_^+1.2^days (5.6%) and Dt_BC_=-59.4_-1.3_^+1.3^days (2.2%). In addition, the close image pair A1-A2 of the lensed quasars can be resolved in the MPIA 2.2m data. We measure a time delay consistent with zero in this pair of images. We also explore the prior distributions of microlensing time-delay potentially affecting the cosmological time-delay measurements of WFI2033-4723. There is however no strong indication in our measurements that microlensing time delay is neither present nor absent. This work is part of a H0LiCOW series focusing on measuring the Hubble constant from WFI2033-4723.
667. Quasar absorption-line systems
ID:
ivo://CDS.VizieR/J/AJ/112/62
Title:
Quasar absorption-line systems
Short Name:
J/AJ/112/62
Date:
21 Oct 2021
Publisher:
CDS
Description:
A survey of quasar absorbers was conducted using the Infrared Astronomical Satellite (IRAS) database. Quasars with known intervening absorption-line systems and broad absorption line (BAL) QSOs were selected primarily from Junkkarinen et al. (1991ApJS...77..203J). Of the 570 quasars with IRAS data, 52 showed 3{sigma} or better detections in at least one band in SCANPI analysis. The origin of the IRAS flux could be from the absorption-line systems, other galaxies, or the quasar itself. The spectral energy distributions for quasars detected in the absorption-line sample and BAL QSOs were found to be redder than those of two control samples which suggests that some of the IRAS flux may arise in dust associated with the intervening galaxies. IRAS SUPERSCANPI processing was carried out for 77 quasars with known MgII absorption at Zabs<1 to investigate the ensemble far-infrared properties of these objects. SUPERSCANPI processing evaluates the median flux for many different positions on the sky, resulting in an improvement in the effective sensitivity. A control sample consisting of objects with no MgII absorption known at Zabs<1 but with the same distribution of absolute V-magnitude, Zem and radio-loud fraction for the background quasars was also processed. The MgII sample was detected at 3{sigma} or better in all four IRAS bands with a significantly larger flux than the control sample at 60{mu}m and 100{mu}m. If this far-infrared emission is from the absorber galaxies, then the far-infrared luminosity of the composite MgII absorber was found to be comparable to that of a starbursting galaxy, although such a high star-formation rate is inconsistent with the optical and near-infrared colors of low-redshift MgII systems. Four of the quasars with individual IRAS detections have intervening galaxies identified with the MgII absorption-lines. The spectral energy distributions of these galaxies imply far-infrared luminosities in excess of what Arp 220 would give at their redshifts. While all the external evidence suggests that the detection of far-infrared emission from the absorber sample may not be connected to the presence of the MgII absorber, we discuss future observations which may help explain our results.
668. Quasar and radio galaxies flux densities
ID:
ivo://CDS.VizieR/J/A+A/319/757
Title:
Quasar and radio galaxies flux densities
Short Name:
J/A+A/319/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
The tables described below contain the data used in the analysis. The data have been taken from various sources in the literature. The references to the data can be found in the paper. Table 1 contains the data of the 3C radio galaxy sample. Table 2 contains the data of the 3C quasar sample. Table 3 contains the data of the 4C quasar sample. The tables list the name of the object, its redshift, the value of the Q-parameter (ratio between the core and extended flux at 5 GHz observed frequency), and the flux densities at various frequencies.
669. Quasar black hole masses
ID:
ivo://CDS.VizieR/J/ApJ/669/791
Title:
Quasar black hole masses
Short Name:
J/ApJ/669/791
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the time-dependent variations of ultraviolet (UV) black hole mass estimates of quasars in the Sloan Digital Sky Survey (SDSS). From SDSS spectra of 615 high-redshift (1.69<z<4.75) quasars with spectra from two epochs, we estimate black hole masses using a single-epoch technique, which employs an additional, automated night-sky line removal and relies on UV continuum luminosity and CIV {lambda}1549 emission-line dispersion. Mass estimates show variations between epochs at about the 30% level for the sample as a whole. We determine that for our full sample, measurement error in the line dispersion likely plays a larger role than the inherent variability in terms of contributing to variations in mass estimates between epochs. However, we use the variations in quasars with r-band spectral signal-to-noise ratio greater than 15 to estimate that the contribution to these variations from inherent variability is roughly 20%. We conclude that these differences in black hole mass estimates between epochs indicate that variability does not make a large contribution to the current factor of 2 scatter between mass estimates derived from low- and high-ionization emission lines.
670. Quasar Candidates
ID:
ivo://CDS.VizieR/VII/143
Title:
Quasar Candidates
Short Name:
VII/143
Date:
21 Oct 2021
Publisher:
CDS
Description:
This data set is based on data in three publications. The positions and magnitudes of quasar candidates discovered on Canada-France Hawaii-Telescope (CFHT) blue green plates are given. Spectroscopy with the Multiple Mirror Telescope (MMT) indicates that 70 percent of the candidates are quasars, and most of the others are white dwarfs or hot subluminous stars. Most of the redshifts are less than z=1.7. Additional spectroscopic observations at Steward Observatory were used. The catalog lists a name based on position, B1950 position, B magnitude, or visual magnitude, redshift, and remarks.