Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to ...the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ–RL dichotomy among type 1 sources. 3C 57 is an atypical RL quasar that shows both uncertain radio morphology and falls in a region of 4DE1 space where RL quasars are rare. We present new radio flux and optical spectroscopic measures designed to verify its atypical optical/UV spectroscopic behaviour and clarify its radio structure. The former data confirms that 3C 57 falls off the 4DE1 quasar ‘main sequence’ with both extreme optical Fe ii emission (
$R_{\rm Fe\,\small {II}}$
∼ 1) and a large C iv λ1549 profile blueshift (∼−1500 km s−1). These parameter values are typical of extreme Population A sources which are almost always RQ. New radio measures show no evidence for flux change over a 50+ year time-scale consistent with compact steep-spectrum (or young LD) over core-dominated morphology. In the 4DE1 context where LD RL are usually low L/L
Edd quasars, we suggest that 3C 57 is an evolved RL quasar (i.e. large blackhole mass) undergoing a major accretion event leading to a rejuvenation reflected by strong Fe ii emission, perhaps indicating significant heavy metal enrichment, high bolometric luminosity for a low-redshift source and resultant unusually high Eddington ratio giving rise to the atypical C iv λ1549.
Broad emission lines in quasars enable us to “resolve” structure and kinematics of the broad-line emitting region (BLR) thought to involve an accretion disk feeding a supermassive black hole. ...Interpretation of broad line measures within the 4DE1 formalism simplifies the apparent confusion among such data by contrasting and unifying properties of so-called high and low accreting Population A and B sources. Hβ serves as an estimator of black hole mass, Eddington ratio and source rest frame; the latter being a valuable input for Civλ1549 studies which allow us to isolate the blueshifted wind component. Optical and HST-UV spectra yield Hβ and Civλ1549 spectra for low-luminosity sources while VLT-ISAAC and FORS and TNG-LRS provide spectra for high-luminosity sources. New high-S/N data for Civ in high-luminosity quasars are presented here for comparison with the other previously published data. Comparison of Hβ and Civλ1549 profile widths/shifts indicates that much of the emission from the two lines arise in regions with different structure and kinematics. Covering a wide range of luminosity and redshift shows evidence for a correlation between Civλ1549 blueshift and source Eddington ratio, with a weaker trend with source luminosity (similar amplitude outflows are seen over four of the five dex luminosity ranges in our combined samples). At low luminosity (z ≲ 0.7) only Population A sources show evidence for a significant outflow while at high luminosity the outflow signature begins to appear in Population B quasars as well.
Context. The Mg II emission line is visible in the optical band for intermediate redshift quasars (0.4 < z < 1.6) and it is thus an extremely important tool to measure the black hole mass and to ...understand the structure of the Broad line region (BLR). Aims. We aim to determine the substructure and the variability of the Mg II line with the aim to identify which part of the line comes from a medium in Keplerian motion. Methods. Using the Southern African Large Telescope (SALT) with the Robert Stobie Spectrograph (RSS) we performed ten spectroscopic observations of quasar HE 0435-4312 (z = 1.2231) over a period of three years (Dec. 23/24, 2012 to Dec. 7/8, 2015). Results. Both the Mg II line and the Fe II pseudo-continuum increase with time. We clearly detect the systematic shift of the Mg II line with respect to the Fe II over the years, corresponding to the acceleration of 104 ± 14 km s-1 yr-1 in the quasar rest frame. The Mg II line shape is clearly non-Gaussian but single-component, and the increase in line equivalent width and line shift is not accompanied with significant evolution of the line shape. We analyse the conditions in the Mg II and Fe II formation region and we note that the very large difference in the covering factor and the turbulent velocity also support the conclusion that the two regions are spatially separated. Conclusions. The measured acceleration of the line systematic shift is too large to connect it with the orbital motion at a distance of the BLR in this source. It may imply a precessing inner disk illuminating the BLR. Further monitoring is still needed to better constrain the variability mechanism.
OIII
λ
5007
“blue outliers”—that are suggestive of outflows in the narrow line region of quasars—appear to be much more common at intermediate
z
(high luminosity) than at low
z
. About
40
%
of ...quasars in a Hamburg ESO intermediate
z
sample of 52 sources qualify as “blue outliers” (i.e., quasars with
OIII
λ
λ
4959
,
5007
lines showing large systematic blueshifts with respect to rest frame). We discuss major findings on what has become an intriguing field in active galactic nuclei research and stress the relevance of “blue outliers” to feedback and host galaxy evolution.
Black hole mass estimates in quasars Marziani, P.; del Olmo, A.; Martínez-Carballo, M. A. ...
Astronomy and astrophysics (Berlin),
07/2019, Volume:
627
Journal Article
Peer reviewed
Open access
Context. The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the structure and dynamics of the quasar broad line region (BLR), including ...perhaps the earliest unambiguous evidence in favor of a disk + wind structure in radio-quiet quasars. Aims. We carried out an analysis of the C IVλ1549 and Hβ line profiles of 28 Hamburg-ESO high-luminosity quasars and of 48 low-z, low-luminosity sources in order to test whether the width of the high-ionization line C IVλ1549 could be correlated with Hβ and be used as a virial broadening estimator. Methods. We analyze intermediate- to high-S/N, moderate-resolution optical and near-infrared (NIR) spectra covering the redshifted C IVλ1549 and Hβ over a broad range of luminosity log L ∼ 44 − 48.5 erg s−1 and redshift (0 − 3), following an approach based on the quasar main sequence. Results. The present analysis indicates that the line width of C IVλ1549 is not immediately offering a virial broadening estimator equivalent to Hβ. At the same time a virialized part of the BLR appears to be preserved even at the highest luminosities. We suggest a correction to FWHM(C IVλ1549) for Eddington ratio (using the C IVλ1549 blueshift as a proxy) and luminosity effects that can be applied over more than four dex in luminosity. Conclusions. Great care should be used in estimating high-L black hole masses MBH from C IVλ1549 line width. However, once a corrected FWHM C IVλ1549 is used, a C IVλ1549-based scaling law can yield unbiased MBH values with respect to the ones based on Hβ with sample standard deviation ≈0.3 dex.
We present composite UV spectra for low-redshift type 1 active galactic nuclei binned to exploit the information content of the eigenvector 1 (E1) parameter space. Composite spectra show high enough ...S/N and spectral resolution to permit a decomposition of the C IV lambda 1549 line profile: one of the strongest high-ionization lines (HILs), and fundamental in defining E1 space. The simplest C IV lambda 1549 decomposition into narrow-line region (NLR), broad-line region (BLR), and very broad line region (VBLR) components suggests that different components have an analog in H beta with two major exceptions. VBLR emission is seen only in population B FWHM(H beta sub(BC)) > 4000 km s super(-1) sources. A blueshifted/asymmetric BLR component is seen only in population A FWHM(H beta sub(BC)) less than or equal to 4000 km s super(-1) HILs such as C IV lambda 1549. The blueshifted component is thought to arise in a high-ionization wind or outflow. Our analysis suggests that such a wind can only be produced in population A (almost all radio-quiet, RQ) sources, where the accretion rate is relatively high. We propose a model to account for several differences between low- and high-ionization line profiles. Part of the broad-line emission is attributed to a self-gravitating/fragmented region in an accretion disk. An inner, optically thick, geometrically thin region of the flow may give rise to a wind/outflow and produce the blueshifted HIL spectrum in population A sources. The fragmented region may produce all or most of the broad-line emission in population B, which contains RQ and the majority of radio-loud (RL) quasars. Comparisons between broad UV lines in RL and RQ sources in a single, well-populated E1 parameter space bin (B1) shows few significant differences. Clear evidence is found for a significant NLR C IV component in most RL sources. The BLR/VBLR similarity in bin B1 provides circumstantial evidence in favor of black hole (BH) spin, rather than BH mass or accretion rate, as a key trigger in determining whether an object will be RL or RQ. We find a 10-fold decrease in EW C IV lambda 1549 with Eddington ratio (decreasing from approximately 1 to similar to 0.01), while N V lambda 1240 shows no change. These trends suggest a luminosity-independent "Baldwin effect" in which the physical driver may be the Eddington ratio.
The hybrid solution for the Fundamental Plane D'Onofrio, M; Fasano, G; Moretti, A ...
Monthly notices of the Royal Astronomical Society,
10/2013, Volume:
435, Issue:
1
Journal Article
Peer reviewed
Open access
By exploiting the data base of early-type galaxy (ETG) members of the WINGS survey of nearby clusters, we address here the long debated question of the origin and shape of the Fundamental Plane (FP). ...Our data suggest that different physical mechanisms concur in shaping and 'tilting' the FP with respect to the virial plane (VP) expectation. In particular, a 'hybrid solution' in which the structure of galaxies and their stellar population are the main contributors to the FP tilt seems to be favoured. We find that the bulk of the tilt should be attributed to structural non-homology, while stellar population effects play an important but less crucial role. In addition, our data indicate that the differential FP tilt between the V and K band is due to a sort of entanglement between structural and stellar population effects, for which the inward steepening of colour profiles (V − K) tends to increase at increasing the stellar mass of ETGs. The same kind of analysis applied to the ATLAS3D and Sloan Digital Sky Survey (SDSS) data in common with WINGS (WSDSS throughout the paper) confirms our results, the only remarkable difference being the less important role that our data attribute to the stellar mass-to-light-ratio (stellar populations) in determining the FP tilt. The ATLAS3D data also suggest that the FP tilt depends as well on the dark matter (DM) fraction and on the rotational contribution to the kinetic energy (V
rot/σ), thus again pointing towards the above-mentioned 'hybrid solution'. We show that the global properties of the FP, i.e. its tilt and tightness, can be understood in terms of the underlying correlation among mass, structure and stellar population of ETGs, for which, at increasing the stellar mass, ETGs become (on average) 'older' and more centrally concentrated. Finally, we show that a Malmquist-like selection effect may mimic a differential evolution of the mass-to-light ratio for galaxies of different masses. This should be taken into account in the studies investigating the amount of the so-called 'downsizing' phenomenon.
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