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We present geometric and dynamical modeling of the broad line region (BLR) for the multi-wavelength reverberation mapping campaign focused on NGC 5548 in 2014. The data set includes photometric and spectroscopic monitoring in the optical and ultraviolet, covering the Hβ, C iv, and Ly broad emission lines. We find an extended disk-like Hβ BLR with a mixture of near-circular and outflowing gas trajectories, while the C iv and Ly BLRs are much less extended and resemble shell-like structures. There is clear radial structure in the BLR, with C iv and Ly emission arising at smaller radii than the Hβ emission. Using the three lines, we make three independent black hole mass measurements, all of which are consistent. Combining these results gives a joint inference of . We examine the effect of using the V band instead of the UV continuum light curve on the results and find a size difference that is consistent with the measured UV-optical time lag, but the other structural and kinematic parameters remain unchanged, suggesting that the V band is a suitable proxy for the ionizing continuum when exploring the BLR structure and kinematics. Finally, we compare the Hβ results to similar models of data obtained in 2008 when the active galactic nucleus was at a lower luminosity state. We find that the size of the emitting region increased during this time period, but the geometry and black hole mass remained unchanged, which confirms that the BLR kinematics suitably gauge the gravitational field of the central black hole.

Mrk 590 is a known changing-look active galactic nuclei (AGNs) which almost turned off in 2012, and then in 2017 partially re-ignited into a repeat flaring state, unusual for an AGN. Our Swift observations since 2013 allow us to characterize the accretion-generated emission and its reprocessing in the central engine of a changing-look AGN. The X-ray and UV variability amplitudes are higher than those typically observed in 'steady-state' AGN at similar moderate accretion rates; instead, the variability is similar to that of highly accreting AGN. The unusually strong X-ray to UV correlation suggests that the UV-emitting region is directly illuminated by X-ray outbursts. We find evidence that the X-rays are reprocessed by two UV components, with the dominant one at ∼3 d and a faint additional reprocessor at near-zero lag. However, we exclude a significant contribution from diffuse broad line region continuum, known to contribute for bonafide AGN. A near-zero lag is expected for a standard 'lamp-post' disc reprocessing model with a driving continuum source near the black hole. That the overall UV response is dominated by the ∼3-d lagged component suggests a complicated reprocessing geometry, with most of the UV continuum not produced in a compact disc, as also found in recent studies of NGC 5548 and NGC 4151. None the less, the observed flares display characteristic time-scales of ∼100 rest-frame days, consistent with the expected thermal time-scale in an accretion disc. [ABSTRACT FROM AUTHOR]

We present a dynamical study of the narrow-line regions in two nearby type 2 quasars (QSO2s). We construct dynamical models based on detailed photoionization models of the emission-line gas, including the effects of internal dust, to apply to observations of large-scale outflows from these active galactic nuclei (AGNs). We use Mrk 477 and Mrk 34 in order to test our models against recent Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations of [O  iii ] emission-line kinematics, since these AGNs possess more energetic outflows than found in Seyfert galaxies. We find that the outflows within 500 pc are consistent with radiative acceleration of dusty gas, however the outflows in Mrk 34 are significantly more extended and may not be directly accelerated by radiation. We characterize the properties of X-ray winds found from the expansion of [O  iii ]-emitting gas close to the black hole. We show that such winds possess the kinetic energy density to disturb [O  iii ] gas at ∼1.8 kpc, and have sufficient energy to entrain the [O  iii ] clouds at ∼1.2 kpc. Assuming that the X-ray wind possesses the same radial mass distribution as the [O  iii ] gas, we find that the peak kinetic luminosity for this wind is 2 per cent of Mrk 34's bolometric luminosity, which is in the 0.5–5 per cent range required by some models for efficient feedback. Our work shows that, although the kinetic luminosity as measured from [O  iii ]-emitting gas is frequently low, X-ray winds may provide more than one order of magnitude higher kinetic power. [ABSTRACT FROM AUTHOR]

We use Hubble Space Telescope /Space Telescope Imaging Spectrograph long-slit G430M and G750M spectra to analyse the extended [O  iii ] λ5007 emission in a sample of 12 nearby (z < 0.12) luminous (L bol > 1.6 × 1045 erg s−1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of ionized gas and their role in active galactic nucleus feedback. We measure fluxes and velocities as functions of radial distances. Using cloudy models and ionizing luminosities derived from [O  iii ] λ5007, we are able to estimate the densities for the emission-line gas. From these results, we derive masses of [O  iii ]-emitting gas, mass outflow rates, kinetic energies, kinetic luminosities, momenta, and momentum flow rates as a function of radial distance for each of the targets. For the sample, masses are several times |$10^{3}$| – |$10^{7}\, {\rm M_{\odot }}$| and peak outflow rates are from 9.3 × 10−3 to |$10.3\, {\rm M_{\odot }}\, {\rm yr^{-1}}$|⁠. The peak kinetic luminosities are (3.4 × 10−8)–(4.9 × 10−4) of the bolometric luminosity, which does not approach the (5.0 × 10−3)–(5.0 × 10−2) range required by some models for efficient feedback. For Mrk 34, which has the largest kinetic luminosity of our sample, in order to produce efficient feedback there would have to be 10 times more [O  iii ]-emitting gas than that we detected at its position of maximum kinetic luminosity. Three targets show extended [O  iii ] emission, but compact outflow regions. This may be due to different mass profiles or different evolutionary histories. [ABSTRACT FROM AUTHOR]

We derive a distance of 15.8 ± 0.4 Mpc to the archetypal Seyfert 1 galaxy NGC 4151 based on the near-infrared Cepheid period–luminosity relation and new Hubble Space Telescope multiband imaging. This distance determination, based on measurements of 35 long-period (P > 25 days) Cepheids, will support the absolute calibration of the supermassive black hole mass in this system, as well as studies of the dynamics of the feedback or feeding of its active galactic nucleus. [ABSTRACT FROM AUTHOR]

The structure of the broad-line region (BLR) is an essential ingredient in the determination of active galactic nucleus (AGN) virial black hole masses, which in turn are important to study the role of black holes in galaxy evolution. Constraints on the BLR geometry and dynamics can be obtained from velocity-resolved studies using reverberation mapping data (i.e. monitoring data). However, monitoring data are observationally expensive and only available for a limited sample of AGNs, mostly confined to the local Universe. Here, we explore a new version of a Bayesian inference, physical model of the BLR that uses an individual spectrum and prior information on the BLR size from the radius–luminosity relation, to model the AGN BLR geometry and dynamics. We apply our model to a sample of 11 AGNs, which have been previously modelled using monitoring data. Our single-epoch BLR model is able to constrain some of the BLR parameters with inferred parameter values that agree within the uncertainties with those determined from the modelling of monitoring data. We find that our model is able to derive stronger constraints on the BLR for AGNs with broad emission lines that qualitatively have more substructure and more asymmetry, presumably as they contain more information to constrain the physical model. The performance of this model makes it a practical and cost-effective tool to determine some of the BLR properties of a large sample of low- and high-redshift AGNs, for which monitoring data are not available. [ABSTRACT FROM AUTHOR]

We show that individual (single-epoch) spectra of active galactic nuclei (AGNs) can constrain some of the geometry and dynamics of the AGN broad line region. Studies of the cosmic influence of supermassive black holes are limited by the current large uncertainties in the determination of black hole masses. One dominant limitation is the unknown geometry, dynamics, and line-of-sight inclination of the broad line region, used to probe the central black hole mass. Recent progress has been made to constrain the spatial and kinematic structure of the broad line region using dynamical modelling of AGN monitoring data and an underlying physical model for the broad line region. In this work we test the ability of a modified version of this dynamical modelling code to constrain the broad line region structure using single-epoch spectra. We test our modelling code on single-epoch spectra of nearby Arp 151 by comparing our results with those obtained with monitoring data of this same object. We find that a significant fraction of the broad line region parameters can indeed be adequately constrained, with uncertainties that are comparable to, or at most a factor of approximately a few higher than those obtained from modelling of monitoring data. Considering the wealth of available single-epoch spectroscopic observations, this method is promising for establishing the overall AGN population trends in the geometry and dynamics of the broad line region. This method can be applied to spectra of AGNs at low and high redshift making it valuable for studies of cosmological black hole and AGN evolution. [ABSTRACT FROM AUTHOR]

Optical changing-look Active Galactic Nuclei (AGN) are a class of sources that change type within a short time-scale of years or decades. This change is characterized by the appearance or disappearance of broad emission lines, often associated with dramatic AGN continuum flux changes that are orders of magnitude larger than those expected from typical AGN variability. In this work we study for the first time the host galaxy of a changing-look AGN, Mrk 590, using high spatial resolution optical and near-infrared observations. We discover that after ∼10 yr absence, the optical broad emission lines of Mrk 590 have reappeared. The AGN optical continuum flux however is still ∼10 times lower than that observed during the most luminous state in the 1990s. The host galaxy shows a 4.5 kpc radius star-forming ring with knots of ionized and cold molecular gas emission. Extended ionized and warm molecular gas emission is detected in the nucleus, indicating that there is a reservoir of gas as close as 60 pc from the black hole. We observe a nuclear gas spiral between radii r ∼ 0.5 and 2 kpc, which has been suggested as a dynamical mechanism able to drive the necessary gas to fuel AGN. We also discover blue-shifted and high velocity dispersion [O  iii ] emission out to a radius of 1 kpc, tracing a nuclear gas outflow. The gas dynamics in Mrk 590 suggest a complex balance between gas inflow and outflow in the nucleus of the galaxy. [ABSTRACT FROM AUTHOR]

Disc reverberation mapping of a handful of nearby active galactic nuclei (AGNs) suggests accretion disc sizes that are a factor of a few too large for their luminosities, apparently at odds with the standard model. Here, we investigate the likely contribution to the measured delay signature of diffuse continuum emission arising from broad-line region gas. We start by constructing spherically symmetric pressure-law BLR models (i.e. P (r)∝ r − s ) that approximately reproduce the observed emission line fluxes of the strong UV–optical emission lines in the best-studied source, NGC 5548. We then determine the contribution of the diffuse continuum to the measured continuum flux and inter-band delays, accounting for the observed variability behaviour of the ionizing nuclear continuum. Those pressure-law models that approximately reproduce the observed emission-line luminosities unavoidably produce substantial diffuse continuum emission. This causes a significant contamination of the disc reverberation signature (i.e. wavelength-dependent continuum delays). Qualitatively, the diffuse continuum delay signatures produced by our models resemble that observed for NGC 5548, including the deviation of the lag spectrum above that of a simple power law in wavelength, short-ward of the Balmer and Paschen jumps. Furthermore, for reasonable estimates of the BLR covering fraction, the delay induced by diffuse continuum emission causes elevated inter-band delays over the entire UV–optical regime; for these pressure-law models, there are no 'disc-dominated' wavelength intervals. Thus, the diffuse continuum contribution must be taken into account in order to correctly infer AGN accretion disc sizes based on inter-band continuum delays. [ABSTRACT FROM AUTHOR]

We study the host galaxies of four Iron Low-Ionization Broad Absorption-line Quasars (FeLoBALs), using Hubble Space Telescope imaging data, investigating the possibility that they represent a transition between an obscured active galactic nucleus (AGN) and an ordinary optical quasar. In this scenario, the FeLoBALs represent the early stage of merger-triggered accretion, in which case their host galaxies are expected to show signs of an ongoing or recent merger. Using PSF subtraction techniques, we decompose the images into host galaxy and AGN components at rest-frame ultraviolet and optical wavelengths. The ultraviolet is sensitive to young stars, while the optical probes stellar mass. In the ultraviolet we image at the BAL absorption trough wavelengths so as to decrease the contrast between the quasar and host galaxy emission. We securely detect an extended source for two of the four FeLoBALs in the rest-frame optical; a third host galaxy is marginally detected. In the rest-frame UV we detect no host emission; this constrains the level of unobscured star formation. Thus, the host galaxies have observed properties that are consistent with those of non-BAL quasars with the same nuclear luminosity, i.e. quiescent or moderately star-forming elliptical galaxies. However, we cannot exclude starbursting hosts that have the stellar UV emission obscured by modest amounts of dust reddening. Thus, our findings also allow the merger-induced young quasar scenario. For three objects, we identify possible close companion galaxies that may be gravitationally interacting with the quasar hosts. [ABSTRACT FROM AUTHOR]

We present and analyse quasi-simultaneous multi-epoch spectral energy distributions (SEDs) of seven reverberation-mapped active galactic nuclei (AGNs) for which accurate black hole mass measurements and suitable archival data are available from the 'AGNWatch' monitoring programs. We explore the potential of optical-UV and X-ray data, obtained within 2 d, to provide more accurate SED-based measurements of individualAGNand quantify the impact of source variability on key measurements typically used to characterize the black hole accretion process plus on bolometric correction factors at 5100 Å, 1350Å and for the 2-10 keV X-ray band, respectively. The largest SED changes occur on long time-scales (≥1 year). For our small sample, the 1μm to 10 keV integrated accretion luminosity typically changes by 10 per cent on short time-scales (over 20 d), by ~30 per cent over a year, but can change by 100 per cent or more for individual AGN. The extreme ultraviolet (EUV) gap is the most uncertain part of the intrinsic SED, introducing a ~25 per cent uncertainty in the accretion-induced luminosity, relative to the model independent interpolation method that we adopt. That aside, our analysis shows that the uncertainty in the accretion-induced luminosity, the Eddington luminosity ratio and the bolometric correction factors can be reduced (by a factor of two or more) by use of the SEDs built from data obtained within 20 d. However, Ṁ and η are mostly limited by the unknown EUV emission and the unknown details of the central engine and our aspect angle. [ABSTRACT FROM AUTHOR]

The sub-population of quasars reddened by intrinsic or intervening clouds of dust are known to be underrepresented in optical quasar surveys. By defining a complete parent sample of the brightest and spatially unresolved quasars in the COSMOS field, we quantify to which extent this sub-population is fundamental to our understanding of the true population of quasars. By using the available multiwavelength data of various surveys in the COSMOS field, we built a parent sample of 33 quasars brighter than J = 20 mag, identified by reliable X-ray to radio wavelength selection techniques. Spectroscopic follow-up with the NOT/ALFOSC was carried out for four candidate quasars that had not been targeted previously to obtain a 100% redshift completeness of the sample. The population of high AV quasars (HAQs), a specific sub-population of quasars selected from optical/near-infrared photometry, some of which were shown to be missed in large optical surveys such as SDSS, is found to contribute 21%-5+9 of the parent sample. The full population of bright spatially unresolved quasars represented by our parent sample consists of 39%-8+9 reddened quasars defined by having AV > 0:1, and 21%-5+9 of the sample having E(B-V) > 0:1 assuming the extinction curve of the Small Magellanic Cloud. We show that the HAQ selection works well for selecting reddened quasars, but some are missed because their optical spectra are too blue to pass the g - r color cut in the HAQ selection. This is either due to a low degree of dust reddening or anomalous spectra. We find that the fraction of quasars with contributing light from the host galaxy, causing observed extended spatial morphology, is most dominant at z ≲ 1. At higher redshifts the population of spatially unresolved quasars selected by our parent sample is found to be representative of the full population of bright active galactic nuclei at J < 20 mag. This work quantifies the bias against reddened quasars in studies that are based solely on optical surveys. [ABSTRACT FROM AUTHOR]