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We report the results of reverberation mapping of three bright Seyfert galaxies, Mrk 79, NGC 3227, and Mrk 841, from a campaign conducted from 2016 December to 2017 May with the Wyoming Infrared Observatory (WIRO) 2.3 m telescope. All three of these targets have shown asymmetric broad Hβ emission lines in the past, although their emission lines were relatively symmetric during our observations. We measured Hβ time lags for all three targets and estimated masses of their black holes—for the first time in the case of Mrk 841. For Mrk 79 and NGC 3227, the data are of sufficient quality to resolve distinct time lags as a function of velocity and to compute two-dimensional velocity-delay maps. Mrk 79 shows smaller time lags for high-velocity gas, but the distribution is not symmetric, and its complex velocity-delay map could result from the combination of both inflowing and outflowing Hβ emitting disks that may be part of a single larger structure. NGC 3227 shows the largest time lags for blueshifted gas, and the two-dimensional velocity-delay map suggests a disk with some inflow. We compare our results with previous work and find evidence for different time lags despite similar luminosities, as well as evolving broad-line region structures. [ABSTRACT FROM AUTHOR]

We report on the results of a new spectroscopic monitoring campaign of the quasar PG 0026+129 at the Calar Alto Observatory 2.2 m telescope from 2017 July to 2020 February. Significant variations in the fluxes of the continuum and broad emission lines, including Hβ and He ii , were observed in the first and third years, and clear time lags between them are measured. The broad Hβ line profile consists of two Gaussian components: an intermediate-width H with an FWHM of 1964 ± 18 and another very broad H with an FWHM of 7570 ± 83. H has long time lags of ∼40–60 days in the rest frame, while H shows nearly zero time delay with respect to the optical continuum at 5100 Å. The velocity-resolved delays show consistent results: lags of ∼30–50 days at the core of the broad Hβ line and roughly zero lags at the wings. H has a redshift of ∼400 , which seems to be stable for nearly 30 yr by comparing with archived spectra, and may originate from an infall. The rms spectrum of H shows a double-peaked profile with brighter blue peak and extended red wing in the first year, which matches the signature of a thin disk. Both the double-peaked profile and the near-zero lag suggest that H comes from a region associated with the part of the accretion disk that emits the optical continuum. Adopting the FWHM (in the rms spectrum) and the time lag measured for the total Hβ line, and a virial factor of 1.5, we obtain a virial mass of for the central black hole in this quasar. [ABSTRACT FROM AUTHOR]

Radial-velocity monitoring has revealed the presence of moving broad emission lines in some quasars, potentially indicating the presence of a subparsec binary system. Phase-referenced, near-infrared interferometric observations could map out the binary orbit by measuring the photocenter difference between a broad emission line and the hot dust continuum. We show that astrometric data over several years may be able to detect proper motions and accelerations, confirming the presence of a binary and constraining system parameters. The brightness, redshifts, and astrometric sizes of current candidates are well matched to the capabilities of the upgraded Very Large Telescope Interferometer/GRAVITY+ instrument, and we identify a first sample of 10 possible candidates. The astrometric signature depends on the morphology and evolution of hot dust emission in supermassive black hole binary systems. Measurements of the photocenter offset may reveal binary motion whether the hot dust emission region is fixed to the inner edge of the circumbinary disk, or moves in response to the changing irradiation pattern from an accreting secondary black hole. [ABSTRACT FROM AUTHOR]

Context. The density of the ambient medium around a supermassive black hole (SMBH) and the way it varies with distance plays an important role in our understanding of the inflow-outflow mechanisms in the Galactic centre (GC). This dependence is often fitted by spherical power-law profiles based on observations in the X-ray, infrared (IR), submillimetre (submm), and radio domains. Aims. Nevertheless, the density profile is poorly constrained at the intermediate scales of 1000 Schwarzschild radii (Rs). Here we independently constrain the spherical density profile using the stellar bow shock of the star S2 which orbits the SMBH at the GC with the pericentre distance of 14.4 mas (∼1500 Rs). Methods. Assuming an elliptical orbit, we apply celestial mechanics and the theory of bow shocks that are at ram pressure equilibrium. We analyse the measured IR flux density and magnitudes of S2 in the L′-band (3.8 micron) obtained over seven epochs in the years between 2004–2018. We put an upper limit on the emission from S2's associated putative bow shock and constrain the density profile of the ambient medium. Results. We detect no significant change in S2 flux density until the recent periapse in May 2018. The intrinsic flux variability of S2 is at the level of 2–3%. Based on the dust-extinction model, the upper limit on the number density at the S2 periapse is ∼1.87  ×  109 cm−3, which yields a density slope of at most 3.20. Using the synchrotron bow-shock emission, we obtain the ambient density of ≲1.01  ×  105 cm−3 and a slope of ≲1.47. These values are consistent with a wide variety of media from hot accretion flows to potentially colder and denser media comparable in properties to broad-line-region clouds. However, a standard thin disc can be excluded at the distance of S2's pericentre. Conclusions. With the current photometry sensitivity of 0.01 mag, we are not able to make stringent constraints on the density of the ambient medium in the GC using S2-star observations. We can distinguish between hot accretion flows and thin, cold discs, where the latter can be excluded at the scale of the S2 periapse. Future observations of stars in the S cluster using instruments such as Mid-IR Extremely Large Telescope Imager and Spectrograph at Extremely Large Telescope with the photometric sensitivity of as much as 10−3 mag will allow the GC medium to be probed at intermediate scales at densities as low as ∼700 cm−3 in case of non-thermal bow-shock emission. The new instrumentation, in combination with discoveries of stars with smaller pericentre distances, will help to independently constrain the density profile around Sagittarius A* (Sgr A*). [ABSTRACT FROM AUTHOR]

The usage of the radius–luminosity (R–L) relation for the determination of black hole masses across the cosmic history, as well as its application for cosmological studies, motivates us to analyze its scatter, which has recently increased significantly for both the optical (Hβ) and UV (Mg ii) lines. To this purpose, we determined the scatter along the R–L relation for an up-to-date reverberation-mapped Mg ii sample. Studying linear combinations of the luminosity at 3000 Å with independent parameters such as the FWHM, the UV Fe ii strength (RFe ii ), and the fractional variability (Fvar) for the whole sample, we get only a small decrease in the scatter (dex). Linear combinations with the dimensionless accretion rate () and the Eddington ratio lead to significant reductions of the scatter (dex), albeit both suffering from the interdependency on the observed time delay. After the division into two subsamples considering the median value of the in the full sample, we find that the scatter decreases significantly for the highly accreting subsample. In particular, the smallest scatter of dex is associated with the independent parameter RFe ii , followed by the combination with Fvar with dex. Both of these independent observationally inferred parameters are in turn correlated with and. These results suggest that the large scatter along the R–L relation is driven mainly by the accretion rate intensity. [ABSTRACT FROM AUTHOR]

We present a study on the stellar population and kinematics of globular clusters (GCs) in the peculiar galaxy M85. We obtain optical spectra of 89 GCs at 8 kpc < R < 160 kpc using the MMT/Hectospec. We divide them into three groups, blue/green/red GCs (B/G/RGCs), with their (g − i)0 colors. All GC subpopulations have mean ages of about 10 Gyr, but showing differences in metallicities. The BGCs and RGCs are the most metal-poor ([Z/H] ∼ −1.49) and metal-rich ([Z/H] ∼ −0.45), respectively, and the GGCs are in between. We find that the inner GC system exhibits a strong overall rotation that is entirely due to a disklike rotation of the RGC system. The BGC system shows little rotation. The GGCs show kinematic properties clearly distinct among the GC subpopulations, having higher mean velocities than the BGCs and RGCs and being aligned along the major axis of M85. This implies that the GGCs have an origin different from the other GC subpopulations. The rotation-corrected velocity dispersion of the RGC system is much lower than that of the BGC system, indicating the truncation of the red halo of M85. The BGCs have a flat velocity dispersion profile out to R = 67 kpc, reflecting the dark matter extent of M85. Using the velocity dispersion of the BGC system, we estimate the dynamical mass of M85 to be 3.8 × 1012M⊙. We infer that M85 has undergone merging events lately, resulting in the peculiar kinematics of the GC system. [ABSTRACT FROM AUTHOR]

Quasar broad emission lines are largely powered by photoionization from the accretion continuum. Increased central luminosity will enhance line emissivity in more distant clouds, leading to increased average distance of the broad-line-emitting clouds and decreased averaged line width, which is known as the "breathing" broad-line region. However, different lines breathe differently, and some high-ionization lines, such as C iv , can even show "anti-breathing" where the line broadens when luminosity increases. Using multi-year photometric and spectroscopic monitoring data from the Sloan Digital Sky Survey Reverberation Mapping project, we quantify the breathing effect () of broad Hα, Hβ, Mg ii , C iv , and C iii] for statistical quasar samples over z ≈ 0.1–2.5. We find that Hβ displays the most consistent normal breathing expected from the virial relation (α ∼ −0.25), Mg ii and Hα on average show no breathing (α ∼ 0), and C iv (and similarly C iii] and Si iv) mostly shows anti-breathing (α > 0). The anti-breathing of C iv can be well understood by the presence of a non-varying core component in addition to a reverberating broad-base component, which is consistent with earlier findings. The deviation from canonical breathing introduces extra scatter (a luminosity-dependent bias) in single-epoch virial BH mass estimates due to intrinsic quasar variability, which underlies the long-argued caveats of C iv single-epoch masses. Using the line dispersion instead of FWHM leads to fewer, albeit still substantial, deviations from canonical breathing in most cases. Our results strengthen the need for reverberation mapping to provide reliable quasar BH masses and to quantify the level of variability-induced bias in single-epoch BH masses based on various lines. [ABSTRACT FROM AUTHOR]

We present new near-infrared VLTI/GRAVITY interferometric spectra that spatially resolve the broad Brγ emission line in the nucleus of the active galaxy IRAS 09149−6206. We use these data to measure the size of the broad line region (BLR) and estimate the mass of the central black hole. Using an improved phase calibration method that reduces the differential phase uncertainty to 0.05° per baseline across the spectrum, we detect a differential phase signal that reaches a maximum of ∼0.5° between the line and continuum. This represents an offset of ∼120 μas (0.14 pc) between the BLR and the centroid of the hot dust distribution traced by the 2.3 μm continuum. The offset is well within the dust sublimation region, which matches the measured ∼0.6 mas (0.7 pc) diameter of the continuum. A clear velocity gradient, almost perpendicular to the offset, is traced by the reconstructed photocentres of the spectral channels of the Brγ line. We infer the radius of the BLR to be ∼65 μas (0.075 pc), which is consistent with the radius–luminosity relation of nearby active galactic nuclei derived based on the time lag of the Hβ line from reverberation mapping campaigns. Our dynamical modelling indicates the black hole mass is ∼1 × 108 M⊙, which is a little below, but consistent with, the standard MBH–σ* relation. [ABSTRACT FROM AUTHOR]

We investigate the origin of the soft X-ray excess component in Seyfert galaxies observed when their luminosity exceeds 0.1% of the Eddington luminosity (). The evolution of a dense blob in radiatively inefficient accretion flow (RIAF) is simulated by applying a radiation magnetohydrodynamic code, CANS+R. When the accretion rate onto a black hole exceeds 10% of the Eddington accretion rate (, where c is the speed of light), the dense blob shrinks vertically because of radiative cooling and forms a Thomson thick, relatively cool (∼107–8 K) region. The cool region coexists with the optically thin, hot () RIAF near the black hole. The cool disk is responsible for the soft X-ray emission, while hard X-rays are emitted from the hot inner accretion flow. Such a hybrid structure of hot and cool accretion flows is consistent with the observations of both hard and soft X-ray emissions from "changing-look" active galactic nuclei (CLAGNs). Furthermore, we find that quasi-periodic oscillations (QPOs) are excited in the soft X-ray-emitting region. These oscillations can be the origin of rapid X-ray time variabilities observed in CLAGNs. [ABSTRACT FROM AUTHOR]

Context. Galaxies that hosted many core-collapse supernova (SN) explosions can be used to study the conditions necessary for the formation of massive stars. NGC 2770 was dubbed an SN factory because it hosted four core-collapse SNe in 20 years (three type Ib and one type IIn). Its star formation rate (SFR) was reported to not be enhanced and, therefore, not compatible with such a high SN rate. Aims. We aim to explain the high SN rate of NGC 2770. Methods. We used archival H I line data for NGC 2770 and reinterpreted the Hα and optical continuum data. Results. Even though the continuum-based SFR indicators do not yield high values, the dust-corrected Hα luminosity implies a high SFR, consistent with the high SN rate. Such a disparity between the SFR estimators is an indication of recently enhanced star formation activity because the continuum indicators trace long timescales of the order of 100 Myr, unlike the line indicators, which trace timescales of the order of 10 Myr. Hence, the unique feature of NGC 2770 compared to other galaxies is the fact that it was observed very shortly after the enhancement of the SFR. It also has high dust extinction, E(B − V) above 1 mag. We provide support for the hypothesis that the increased SFR in NGC 2770 is due to the interaction with its companion galaxies. We report an H I bridge between NGC 2770 and its closest companion and the existence of a total of four companions within 100 kpc (one identified for the first time). There are no clear H I concentrations close to the positions of SNe in NGC 2770 such as those detected for hosts of gamma-ray bursts (GRBs) and broad-lined SNe type Ic (IcBL). This suggests that the progenitors of type Ib SNe are not born out of recently accreted atomic gas, as was suggested for GRB and IcBL SN progenitors. [ABSTRACT FROM AUTHOR]

Reverberation results of the flat spectrum radio quasar PKS 1510-089 from 8.5 years of spectroscopic monitoring carried out at Steward Observatory over nine observing seasons between December 2008 and June 2017 are presented. Optical spectra show strong Hβ, Hγ, and Fe II emission lines overlying on a blue continuum. All the continuum and emission line light curves show significant variability with fractional root-mean-square variations of 37.30 ± 0.06% (f5100), 11.88 ± 0.29% (Hβ), and 9.61 ± 0.71% (Hγ); however, along with thermal radiation from the accretion disk, non-thermal emission from the jet also contributes to f5100. Several methods of time series analysis (ICCF, DCF, von Neumann, Bartels, JAVELIN, χ2) are used to measure the lag between the continuum and line light curves. The observed frame broad line region size is found to be 61.1−3.2+4.0 61. 1 − 3.2 + 4.0 $ 61.1^{+4.0}_{-3.2} $ (64.7−10.6+27.1 64. 7 − 10.6 + 27.1 $ 64.7^{+27.1}_{-10.6} $) light-days for Hβ (Hγ). Using the σline of 1262 ± 247 km s−1 measured from the root-mean-square spectrum, the black hole mass of PKS 1510-089 is estimated to be 5.71−0.58+0.62 × 107 M⊙ 5. 71 − 0.58 + 0.62 × 10 7 M ⊙ $ 5.71^{+0.62}_{-0.58} \times 10^{7} M_{\odot} $. [ABSTRACT FROM AUTHOR]

We present reverberation mapping results for the Mg ii λ2800 Å broad emission line in a sample of 193 quasars at with photometric and spectroscopic monitoring observations from the Sloan Digital Sky Survey Reverberation Mapping project during 2014–2017. We find significant time lags between the Mg ii and continuum lightcurves for 57 quasars, and define a "gold sample" of 24 quasars with the most reliable lag measurements. We estimate false-positive rates for each lag that range from 1% to 24%, with an average false-positive rate of 11% for the full sample and 8% for the gold sample. There are an additional ∼40 quasars with marginal Mg ii lag detections, which may yield reliable lags after additional years of monitoring. The Mg ii lags follow a radius–luminosity relation with a best-fit slope that is consistent with , but with an intrinsic scatter of 0.36 dex that is significantly larger than found for the Hβ radius–luminosity relation. For targets with SDSS-RM lag measurements of other emission lines, we find that our Mg ii lags are similar to the Hβ lags and ∼2–3 times larger than the C iv lags. This work significantly increases the number of Mg ii broad-line lags and provides additional reverberation-mapped black hole masses, filling the redshift gap at the peak of supermassive black hole growth between the Hβ and C iv emission lines in optical spectroscopy. [ABSTRACT FROM AUTHOR]

Feedback from active galactic nuclei (AGNs) is expected to impact the amount of cold gas in galaxies by driving strong galactic winds, by preventing external gas inflows, or by changing the thermodynamical state of the gas. We use estimates of molecular gas mass based on dust absorption (Hα/Hβ) to study gas content of large samples of type 2 AGN host galaxies in comparison with inactive galaxies. Using sparse principal component and clustering analysis, we analyze a suite of stellar and structural parameters of ∼27,100 face-on, central galaxies at redshift z = 0.02–0.15 and with stellar mass M⋆ ≈ 1010–2 × 1011M⊙. We identify four galaxy groups of similar mass and morphology (mass surface density, velocity dispersion, concentration, and Sérsic index) that can be evolutionarily linked through a life cycle wherein gas content mediates their star formation rate (SFR) and level of AGN activity. Galaxies first consume their gas mostly through bursty star formation, then enter into a transition phase of intermediate gas richness in which star formation and AGNs coexist, before settling into retirement as gas-poor, quiescent systems with residual levels of AGN activity (LINERs). Strongly accreting black holes (Seyferts) live in gas-rich, star-forming hosts, but neither their gas reservoir nor their ability to form stars seems to be impacted instantaneously (timescales ≲0.5 Gyr) by AGN feedback. Our results are inconsistent with AGN feedback models that predict that central, bulge-dominated, Seyfert-like AGNs in massive galaxies have significantly lower molecular gas fractions than inactive galaxies of similar mass, morphology, and SFR. [ABSTRACT FROM AUTHOR]

The nature of the rare "Changing-look" (CL) phenomenon in active galactic nuclei (AGNs) is still under debate. We present Swift/XRT and UVOT follow-up observations of UGC 3223, a newly discovered repeat CL-AGN with type transitions of S1.5 → S2 → S1.8 occurring in a period of about 30 yr. By comparing the values previously reported in the ROSAT All-sky Survey and in the second Swift-XRT Point Source catalog, we clearly find that the X-ray flux tightly follows the optical spectral transition, in which a spectral type closer to a Seyfert 1 type is associated with a higher X-ray flux. An invariable X-ray spectral shape is, however, found in the CL phenomenon of the object. An extremely low Eddington ratio of ∼2 × 10−4 can be obtained from the X-ray luminosity for its Seyfert 2 state, which suggests the disk-wind broad-line region model best explains the CL phenomenon. A variation of the total UV emission is not revealed when compared to the previous Galaxy Evolution Explorer NUV observation, since the UVOT images indicate that ∼90% UV emission comes from intensive star formation in the host galaxy. [ABSTRACT FROM AUTHOR]

The size of the dust torus in active galactic nuclei (AGNs) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared (MIR) torus emission. This dust reverberation mapping (RM) technique has been successfully applied to ∼70 z ≲ 0.3 AGNs and quasars. Here we present first results of our dust RM program for distant quasars covered in the Sloan Digital Sky Survey Stripe 82 region combining ∼20 yr ground-based optical light curves with 10 yr MIR light curves from the WISE satellite. We measure a high-fidelity lag between W1 band (3.4 μm) and g band for 587 quasars over 0.3 ≲ z ≲ 2 () and two orders of magnitude in quasar luminosity. They tightly follow (intrinsic scatter ∼0.17 dex in lag) the IR lag–luminosity relation observed for z < 0.3 AGNs, revealing a remarkable size–luminosity relation for the dust torus over more than four decades in AGN luminosity, with little dependence on additional quasar properties such as Eddington ratio and variability amplitude. This study motivates further investigations in the utility of dust RM for cosmology and strongly endorses a compelling science case for the combined 10 yr Vera C. Rubin Observatory Legacy Survey of Space and Time (optical) and 5 yr Nancy Grace Roman Space Telescope 2 μm light curves in a deep survey for low-redshift AGN dust RM with much lower luminosities and shorter, measurable IR lags. The compiled optical and MIR light curves for 7384 quasars in our parent sample are made public with this work. [ABSTRACT FROM AUTHOR]

We use multiepoch quasar spectroscopy to determine how accurately single-epoch spectroscopy can locate quasars in emission-line parameter space in order to inform investigations where time-resolved spectroscopy is not available. We explore the improvements in emission-line characterization that result from using nonparametric information from many lines as opposed to a small number of parameters for a single line, utilizing reconstructions based on an independent component analysis applied to the data from the Sloan Digital Sky Survey Reverberation Mapping project. We find that most of the quasars are well described by just two components, while more components signal a quasar likely to yield a successful reverberation mapping analysis. In single-epoch spectroscopy the apparent variability of equivalent width is exaggerated because it is dependent on the continuum. Multiepoch spectroscopy reveals that single-epoch results do not significantly change where quasars are located in C iv parameter space and do not have a significant impact on investigations of the global Baldwin effect. Quasars with emission-line properties indicative of higher L/LEdd are less variable, consistent with models with enhanced accretion disk density. Narrow absorption features at the systemic redshift may be indicative of orientation (including radio-quiet quasars) and may appear in as much as 20% of the quasar sample. Future work applying these techniques to lower-luminosity quasars will be important for understanding the nature of accretion disk winds. [ABSTRACT FROM AUTHOR]

We present nearly 500 days of observations of the tidal disruption event (TDE) ASASSN-18pg, spanning from 54 days before peak light to 441 days after peak light. Our data set includes X-ray, UV, and optical photometry, optical spectroscopy, radio observations, and the first published spectropolarimetric observations of a TDE. ASASSN-18pg was discovered on 2018 July 11 by the All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of d = 78.6 Mpc; with a peak UV magnitude of m ≃ 14, it is both one of the nearest and brightest TDEs discovered to-date. The photometric data allow us to track both the rise to peak and the long-term evolution of the TDE. ASASSN-18pg peaked at a luminosity of L ≃ 2.4 × 1044 erg s−1, and its late-time evolution is shallower than a flux ∝t−5/3 power-law model, similar to what has been seen in other TDEs. ASASSN-18pg exhibited Balmer lines and spectroscopic features consistent with Bowen fluorescence prior to peak, which remained detectable for roughly 225 days after peak. Analysis of the two-component Hα profile indicates that, if they are the result of reprocessing of emission from the accretion disk, the different spectroscopic lines may be coming from regions between ∼10 and ∼60 lt-days from the black hole. No X-ray emission is detected from the TDE, and there is no evidence of a jet or strong outflow detected in the radio. Our spectropolarimetric observations indicate that the projected emission region is likely not significantly aspherical, with the projected emission region having an axis ratio of ≳0.65. [ABSTRACT FROM AUTHOR]

Results from a few decades of reverberation mapping (RM) studies have revealed a correlation between the radius of the broad-line emitting region (BLR) and the continuum luminosity of active galactic nuclei. This "radius–luminosity" relation enables survey-scale black hole mass estimates across cosmic time, using relatively inexpensive single-epoch spectroscopy, rather than intensive RM time monitoring. However, recent results from newer RM campaigns challenge this widely used paradigm, reporting quasar BLR sizes that differ significantly from the previously established radius–luminosity relation. Using simulations of the radius–luminosity relation with the observational parameters of the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, we find that this difference is not likely due to observational biases. Instead, it appears that previous RM samples were biased to a subset of quasar properties, and the broader parameter space occupied by the SDSS-RM quasar sample has a genuinely wider range of BLR sizes. We examine the correlation between the deviations from the radius–luminosity relation and several quasar parameters; the most significant correlations indicate that the deviations depend on the UV/optical spectral energy distribution and the relative amount of ionizing radiation. Our results indicate that single-epoch black hole mass estimates that do not account for the diversity of quasars in the radius–luminosity relation could be overestimated by an average of ∼0.3 dex. [ABSTRACT FROM AUTHOR]

We studied optical-ultraviolet spectral energy distribution of 10 weak emission-line quasars (WLQs) that lie at redshifts z = 0.19 and 1.43 < z < 3.48. The theoretical models of their accretion disk continua are created based on the Novikov–Thorne equations. It allows us to estimate masses of their supermassive black holes () and accretion rates. We determined the virial factor for WLQs and note its anticorrelation with the FWHM of the Hβ emission line). By comparison with the previously estimated BH masses, the underestimation of is noticed with a mean factor of 4–5, which depends on the measured full width. We proposed a new formula to estimate in WLQs based on their observed (Hβ) and luminosities at 5100 Å. In our opinion, WLQs are also normal quasars visible in a reactivation stage. [ABSTRACT FROM AUTHOR]

3C 273 is an intensively monitored flat-spectrum radio quasar with both a beamed jet and blue bump together with broad emission lines. The coexistence of the comparably prominent jet and accretion disk leads to complicated variability properties. Recent reverberation mapping monitoring for 3C 273 revealed that the optical continuum shows a distinct long-term trend that does not have a corresponding echo in the Hβ fluxes. We compile multiwavelength monitoring data from the Swift archive and other ground-based programs and clearly find two components of emissions at optical wavelength. One component stems from the accretion disk itself, and the other component can be ascribed to the jet contribution, which also naturally accounts for the nonechoed trend in reverberation mapping data. We develop an approach to decouple the optical emissions from the jet and accretion disk in 3C 273 with the aid of multiwavelength monitoring data. By assuming that the disk emission has a negligible polarization in consideration of the low inclination of the jet, the results show that the jet contributes a fraction of ∼10% at the minimum and up to ∼40% at the maximum to the total optical emissions. This is the first time to provide a physical interpretation of the "detrending" manipulation conventionally adopted in reverberation mapping analysis. Our work also illustrates the importance of appropriately analyzing variability properties in cases of coexisting jets and accretion disks. [ABSTRACT FROM AUTHOR]

Blazars represent the dominant population of the extragalactic γ‐ray sources in the universe. These sources exhibit some characteristic properties such as strong and nonthermal continuum emission over the entire electromagnetic spectrum, from radio to Tera electron Volts (TeV) γ‐rays, with rapid variability on all timescales. The emission at radio and optical wavelengths is highly polarized with significant variation. The fastest variability in the blazar emission is observed during the flaring activity, which is an important observational property of blazars. In this paper, we describe various methods to characterize the temporal variability in the multiwavelength light curves of blazars. We also provide a detailed description of the set of statistical parameters that are used to quantify the level of variability present in the time series. Implications of the information derived from the variability study to probe the physics of blazars using multiwavelength observations are also discussed. [ABSTRACT FROM AUTHOR]

We present a detailed comparative systematic study using a sample of 221 narrow-line Seyfert 1 (NLSy1) galaxies in comparison to a redshift-matched sample of 154 broad-line Seyfert 1 (BLSy1) galaxies based on their observations using ROSAT and/or XMM-Newton in soft X-ray band (0.1–2.0 keV). A homogeneous analysis is carried out to estimate their soft X-ray photon indices () and its correlations with other parameters of nuclear activities such as Eddington ratios (REdd), bolometric luminosities (Lbol), black hole masses (MBH), and the widths of the broad component of Hβ lines (FWHM(Hβ)). In our analysis, we found clear evidence of the difference in the and REdd distributions among NLSy1 and BLSy1 galaxies, with steeper and higher REdd for the former. Such a difference also exists in the spectral index distribution in hard X-ray (), based on the analysis of 53 NLSy1 and 46 BLSy1 galaxies in the 2–10 keV energy band. The difference in REdd distributions does exist even after applying the average correction for the difference in the inclination angle of NLSy1 and BLSy1 galaxies. We also estimated REdd, based on SED fitting of 34 NLSy1 and 30 BLSy1 galaxies over the 0.3–10 keV energy band, and found that results are still consistent with REdd estimates based on the optical bolometric luminosity. Our analysis suggests that the higher REdd in NLSy1 is responsible for its steeper X-ray spectral slope compared to the BLSy1, consistent with the disk-corona model as proposed for the luminous AGNs. [ABSTRACT FROM AUTHOR]

We present the monitoring of the active galactic nuclei continuum and Mg ii broad-line emission for the quasar HE 0413-4031 (z = 1.38) based on the six-year monitoring by the South African Large Telescope (SALT). We manage to estimate a time-delay of days in the rest frame of the source using seven different methods: interpolated cross-correlation function, discrete correlation function (DCF), z-transformed DCF, JAVELIN, two estimators of data regularity (Von Neumann, Bartels), and χ2 method. This time-delay is below the value expected from the standard radius–luminosity relation. However, based on the monochromatic luminosity of the source and the spectral energy distribution modeling, we interpret this departure as the shortening of the time-delay due to the higher accretion rate of the source, with the inferred Eddington ratio of ∼0.4. The Mg ii line luminosity of HE 0413-4031 responds to the continuum variability as , which is consistent with the light-travel distance of the location of Mg ii emission at Rout ∼ 1018 cm. Using the data of 10 other quasars, we confirm the radius–luminosity relation for the broad Mg ii line, which was previously determined for the broad Hβ line for lower-redshift sources. In addition, we detect a general departure of higher-accreting quasars from this relation in analogy to the Hβ sample. After the accretion-rate correction of the light-travel distance, the Mg ii –based radius–luminosity relation has a small scatter of only 0.10 dex. [ABSTRACT FROM AUTHOR]

Using a high-luminosity (Lbol ∼ 1047.5–1048.3 erg s−1), high-redshift (3.2 < z < 3.8) quasar sample of 19 quasars with optical and near-infrared spectroscopy, we investigate the reliability of the C iv -based black hole mass estimates (MBH). The median logarithm of the C iv - and Hβ-based MBH ratios is 0.110 dex, with a scatter of 0.647 dex. The C iv -to-Hβ BH mass differences are significantly correlated with the C iv FWHMs, blueshifts, and asymmetries. Corrections of the C iv FWHM using the blueshift and asymmetry reduce the scatter of the mass differences by ∼0.04–0.2 dex. Quasars in our sample accrete at the Eddington ratio REDD > 0.3 and cover a considerable range of blueshifts, with 18/19 of the quasars showing C iv blueshifts (with the median value of 1126 km s−1) and 14/19 of the quasars showing C iv blueshifts larger than 500 km s−1. It suggests that not all quasars with high Eddington ratios show large blueshifts. The Baldwin effect between the C iv rest-frame equivalent width (REW) and the continuum luminosity at 1350 Å is not seen, likely due to the limited luminosity range of our sample. We find a lack of flux in the red wing of the composite spectrum with larger C iv blueshift and detect a higher ratio of [O iii ] quasars with REW[O iii ] > 5 Å in the subsample with lower C iv blueshift. It is more likely that they are caused by the combination of the Eddington ratio and the orientation effect. [ABSTRACT FROM AUTHOR]

We compare the microlensing-based continuum emission region size measurements in a sample of 15 gravitationally lensed quasars with estimates of luminosity-based thin disk sizes to constrain the temperature profile of the quasar continuum accretion region. If we adopt the standard thin disk model, we find a significant discrepancy between sizes estimated using the luminosity and those measured by microlensing of log(rL/rμ) = −0.57 ± 0.08 dex. If quasar continuum sources are simple, optically thick accretion disks with a generalized temperature profile , the discrepancy between the microlensing measurements and the luminosity-based size estimates can be resolved by a temperature profile slope 0.37 < β < 0.56 at 1σ confidence. This is shallower than the standard thin disk model (β = 0.75) at 3σ significance. We consider alternate accretion disk models that could produce such a temperature profile and reproduce the empirical continuum size scaling with black hole mass, including disk winds or disks with nonblackbody atmospheres. [ABSTRACT FROM AUTHOR]

We report the discovery of a tidal disruption event (TDE) candidate occurring in the active galactic nucleus (AGN) SDSS J022700.77-042020.6. A sudden increase in flux from J0227-0420 during the second half of 2009 appears in the long-term optical, UV, and near-IR (NIR) light curves. A plateau phase, following an initial decline, is seen in the near-UV (NUV) and optical light curves. We find possible evidence that the plateau in the NUV band may lag behind the optical ones by ∼70–80 days with also a much shorter duration, that is, ∼7–15 days against ∼40–50 days. The long-term NUV/optical (after the plateau phase), NIR, and mid-infrared (MIR) light curves can be well characterized with a form of L(t) ∝ t−β, consistent with the expectation of a TDE. The plateaus can be explained if stellar streams collide with the preexisting disk at different radii. Though the overall fallback rate decreases, the material in the outer disk drifts inward and increases the local accretion rate in the inner region, producing the NUV/optical plateaus. The possible lag is then attributed to viscosity delay. The index β of the NIR J, H, and Ks bands (∼1.4–3.3) is steeper than that of the UV/optical (∼0.7–1.3) and MIR bands (∼0.9–1.8), which may suggest that a certain fraction of the dust in the inner region of the torus may be sublimated during the TDE phase. Our results indicate that, due to collisions between stellar debris and the preexisting disk, the light curves of TDEs occurring in AGNs may show distinctive features, which may shed new light on the accretion process. [ABSTRACT FROM AUTHOR]

We present a method for comparing the Hβ emission-line profiles of observed supermassive black hole (SBHB) candidates and models of subparsec SBHBs in circumbinary disks. Using the approach based on principal component analysis, we infer the values of the binary parameters for the spectroscopic SBHB candidates and evaluate the parameter degeneracies, representative of the uncertainties intrinsic to such measurements. We find that as a population, the SBHB candidates favor the average value of the semimajor axis corresponding to log(a/M) ≈ 4.20 ± 0.42 and comparable mass ratios, q > 0.5. If the SBHB candidates considered are true binaries, this result would suggest that there is a physical process that allows initially unequal-mass systems to evolve toward comparable mass ratios (e.g., accretion that occurs preferentially onto the smaller of the black holes) or point to some, yet unspecified, selection bias. Our method also indicates that the SBHB candidates equally favor configurations in which the mini-disks are coplanar or misaligned with the binary orbital plane. If confirmed for true SBHBs, this finding would indicate the presence of a physical mechanism that maintains misalignment of the mini-disks down to subparsec binary separations (e.g., precession driven by gravitational torques). The probability distributions of the SBHB parameters inferred for the observed SBHB candidates and our control group of AGNs are statistically indistinguishable, implying that this method can in principle be used to interpret the observed emission-line profiles once a sample of confirmed SBHBs is available but cannot be used as a conclusive test of binarity. [ABSTRACT FROM AUTHOR]

We use deep adaptive optics assisted integral field spectroscopy from SINFONI on the VLT to study the spatially resolved properties of ionized gas outflows driven by active galactic nuclei (AGNs) in three galaxies at z ∼ 2.2—K20-ID5, COS4-11337, and J0901 + 1814. These systems probe AGN feedback from nuclear to circumgalactic scales and provide unique insights into the different mechanisms by which AGN-driven outflows interact with their host galaxies. K20-ID5 and COS4-11337 are compact star-forming galaxies with powerful ∼1500 km s−1 AGN-driven outflows that dominate their nuclear Hα emission. The outflows do not appear to have any impact on the instantaneous star formation activity of the host galaxies, but they carry a significant amount of kinetic energy that could heat the halo gas and potentially lead to a reduction in the rate of cold gas accretion onto the galaxies. The outflow from COS4-11337 is propagating directly toward its companion galaxy COS4-11363, at a projected separation of 5.4 kpc. COS4-11363 shows signs of shock excitation and recent truncation of star formation activity, which could plausibly have been induced by the outflow from COS4-11337. J0901 + 1814 is gravitationally lensed, giving us a unique view of a compact (R = 470 ± 70 pc), relatively low-velocity (∼650 km s−1) AGN-driven outflow. J0901 + 1814 has a similar AGN luminosity to COS4-11337, suggesting that the difference in outflow properties is not related to the current AGN luminosity and may instead reflect a difference in the evolutionary stage of the outflow and/or the coupling efficiency between the AGN ionizing radiation field and the gas in the nuclear regions. [ABSTRACT FROM AUTHOR]

We present an observational study of 22 broad absorption line quasars (BAL QSOs) at based on optical/near-IR spectroscopy, aiming to investigate quasar winds and their effects. The near-IR spectroscopy covers the Hβ and/or Mg ii broad emission lines (BELs) for these quasars, allowing us to estimate their central black hole (BH) masses in a robust way. We found that our BAL QSOs, on average, do not have a higher Eddington ratio than that from non-BAL QSOs matched in redshift and/or luminosity. In a subset consisting of seven strong BAL QSOs possessing subrelativistic BAL outflows, we see the prevalence of large C iv BEL blueshift (∼3100 km s−1) and weak [O iii ] emission (particularly the narrow [O iii ] λ5007 component), indicative of nuclear outflows affecting the narrow emission line (NEL) regions. In another subset consisting of 13 BAL QSOs having simultaneous observations of Mg ii and Hβ, we found a strong correlation between 3000 and 5000 Å monochromatic luminosity, consistent with that from non-BAL QSOs matched in redshift and luminosity; however, there is no correlation between Mg ii and Hβ in FWHM, likely due to nuclear outflows influencing the BEL regions. Our spectroscopic investigations offer strong evidence that the presence of nuclear outflows plays an important role in shaping the BEL/NEL regions of these quasars and, possibly, regulating the growth of central supermassive BHs. We propose that BEL blueshift and BALs could be different manifestations of the same outflow system viewed at different sight lines and/or phases. [ABSTRACT FROM AUTHOR]

Significant positional offsets of the value from 1 mas to more than 10 mas were found previously between radio (VLBI) and optical (Gaia) positions of active galactic nuclei (AGNs). They happen preferentially parallel to the parsec-scale jet direction. AGNs with VLBI-to- Gaia offsets pointed downstream the jet are found to have favourably higher optical polarization, as expected if extended optical jets dominate in the emission and shift the Gaia centroid away from the physical nucleus of the source. Upstream offsets with the suggested domination of accretion discs manifest themselves through the observed low optical polarization. Direction of linear optical polarization is confirmed to preferentially align with parsec-scale jets in AGNs with dominant jets consistent with a toroidal magnetic field structure. Our findings support the disc–jet interpretation of the observed positional offsets. These results call on an intensification of AGN optical polarization monitoring programs in order to collect precious observational data. Taken together with the continued VLBI and Gaia observations, they will allow researchers to reconstruct detailed models of the disc–jet system in AGNs on parsec scales. [ABSTRACT FROM AUTHOR]

Context. An unresolved region in the relative vicinity of the event horizon of a supermassive black holes (SMBH) in active galactic nuclei (AGN) radiates strongly variable optical continuum and broad-line emission flux. These fluxes can be processed into twodimensional transfer functions (2DTF) of material flows that encrypt various information about these unresolved structures. An intense search for kinematic signatures of reverberation mapping of close binary SMBH (SMBBH) is currently ongoing. Aims. Elliptical SMBBH systems (i.e. both orbits and disc-like broad-line regions (BLR) are elliptic) have not been assessed in 2DTF studies. We aim to numerically infer such a 2DTF because the geometry of the unresolved region is imprinted on their optical emission. Through this, we determine their specific kinematical signatures. Methods. We simulated the geometry and kinematics of SMBBH whose components are on elliptical orbits. Each SMBH had a disclike elliptical BLR. The SMBHs were active and orbited each other tightly at a subparsec distance. Results. Here we calculate for the first time 2DTF, as defined in the velocity-time delay plane, for several elliptical configurations of SMBBH orbits and their BLRs. We find that these very complex configurations are clearly resolved in maps. These results are distinct from those obtained from circular and disc-wind geometry. We calculate the expected line variability for all SMBBH configurations. We show that the line shapes are influenced by the orbital phase of the SMBBH. Some line profiles resemble observed profiles, but they can also be much deformed to look like those from the disc-wind model. Conclusions. First, our results imply that using our 2DTF, we can detect and quantify kinematic signatures of elliptical SMBBH. Second, the calculated expected line profiles share some intriguing similarities with observed profiles, but also with some profiles that are synthesised in disc-wind models. To overcome the non-uniqueness of the spectral line shapes as markers of SMBBH, they must be accompanied with 2DTF. [ABSTRACT FROM AUTHOR]

We analyze emission line properties and their correlations for 18,043 type 1 active galactic nucleus (AGN) in the range of 0.02 ≤ z ≤ 0.8, based on Sloan Digital Sky Survey Data Release 14 data. We complement the data with photometric measurements from ROSAT, GALEX, 2MASS, and FIRST. We find the following: (a) The average correlation between luminosity of [O III] and AGN luminosity is stronger than those for [O II] line. This is consistent with the stratified model of narrow line region (NLR). Furthermore, we also find a weak dependence of ionization degree with AGN luminosity. (b) The narrow lines luminosity and radio luminosity correlation is stronger for radio quiet AGN and weaker for radio loud (RL) AGN, most likely due to radio jets. A possible explanation is as the jets penetrate the NLR, the shock will ionize its gas, increase the narrow lines emission, and cause a bigger dispersion in the correlation for RL AGN. (c) The investigated narrow lines, [O II], [O III], Hβ, Hα, [N II], and [S II], show a significant trend of decreasing luminosity ratio relative to the broad Hβ luminosity where the slopes in the range of −0.26 to −0.50. We did not find any correlation of the trend slopes with ionization potential or critical density of the lines. We suggest that this correlation is due to decrease in covering factor of NLR as AGN luminosity increases. (d) The EV1 correlation is found in our data and represents change in Eddington ratio. By using L[O III]/L[O II] ratio, we found that the ionization degree decreases as Eddington ratio increases. We also confirm that objects with higher Eddington ratio tend to have narrower Hβ, stronger Fe II emission, and weaker [O III] strength. In contrast to that, objects with lower Eddington ratio tend to have broader Hβ, weaker Fe II emission, and higher [O III] strength. [ABSTRACT FROM AUTHOR]

We report on simultaneous sub-second optical and X-ray timing observations of the low-mass X-ray binary black hole candidate MAXI J1820+070. The bright 2018 outburst rise allowed simultaneous photometry in five optical bands (ugriz s ) with HiPERCAM/GTC (Optical) at frame rates over 100 Hz, together with NICER/ISS observations (X-rays). Intense (factor of 2) red flaring activity in the optical is seen over a broad range of time-scales down to ∼10 ms. Cross-correlating the bands reveals a prominent anticorrelation on time-scales of ∼seconds, and a narrow sub-second correlation at a lag of ≈ +165 ms (optical lagging X-rays). This lag increases with optical wavelength, and is approximately constant over Fourier frequencies of ∼0.3–10 Hz. These features are consistent with an origin in the inner accretion flow and jet base within ∼5000 Gravitational radii. An additional ∼+5 s lag feature may be ascribable to disc reprocessing. MAXI J1820+070 is the third black hole transient to display a clear ∼0.1 s optical lag, which may be common feature in such objects. The sub-second lag variation with wavelength is novel, and may allow constraints on internal shock jet stratification models. [ABSTRACT FROM AUTHOR]

Hydrogen-rich supernovae, known as Type II (SNe II), are the most common class of explosions observed following the collapse of the core of massive stars. We used analytical estimates and population synthesis simulations to assess the fraction of SNe II progenitors that are expected to have exchanged mass with a companion prior to explosion. We estimate that 1/3 to 1/2 of SN II progenitors have a history of mass exchange with a binary companion before exploding. The dominant binary channels leading to SN II progenitors involve the merger of binary stars. Mergers are expected to produce a diversity of SN II progenitor characteristics, depending on the evolutionary timing and properties of the merger. Alternatively, SN II progenitors from interacting binaries may have accreted mass from their companion, and subsequently been ejected from the binary system after their companion exploded. We show that the overall fraction of SN II progenitors that are predicted to have experienced binary interaction is robust against the main physical uncertainties in our models. However, the relative importance of different binary evolutionary channels is affected by changing physical assumptions. We further discuss ways in which binarity might contribute to the observed diversity of SNe II by considering potential observational signatures arising from each binary channel. For supernovae which have a substantial H-rich envelope at explosion (i.e., excluding Type IIb SNe), a surviving non-compact companion would typically indicate that the supernova progenitor star was in a wide, non-interacting binary. We argue that a significant fraction of even Type II-P SNe are expected to have gained mass from a companion prior to explosion. [ABSTRACT FROM AUTHOR]

Context. When can an active galactic nucleus (AGN) be considered radio loud (RL)? Following the established view of the AGNs inner workings, an AGN is RL if associated with relativistic ejections emitting a radio synchrotron spectrum (i.e., it is a "jetted" AGN). In this paper we exploit the AGN main sequence that offers a powerful tool to contextualize radio properties. Aims. If large samples of optically-selected quasars are considered, AGNs are identified as RL if their Kellermann's radio loudness ratio RK >  10. Our aims are to characterize the optical properties of different classes based on radio loudness within the main sequence and to test whether the condition RK >  10 is sufficient for the identification of RL AGNs, since the origin of relatively strong radio emission may not be necessarily due to relativistic ejection. Methods. A sample of 355 quasars was selected by cross-correlating the Very Large Array Faint Images of the Radio Sky at Twenty-Centimeters survey (FIRST) with the twelfth release of the Sloan Digital Sky Survey Quasar Catalog published in 2017. We classified the optical spectra according to their spectral types along the main sequence of quasars. For each spectral type, we distinguished compact and extended morphology (providing a FIRST-based atlas of radio maps in the latter case), and three classes of radio loudness: detected (specific flux ratio in the g band and at 1.4 GHz, R′K < 10 R K ′ < 10 $ R_{\rm K}^{\prime} ), intermediate (10 ≤ R′K < 70 10 ≤ R K ′ < 70 $ 10 \le R_{\rm K}^{\prime} ), and RL (R′K ≥ 70 R K ′ ≥ 70 $ R_{\rm K}^{\prime} \geq 70 $). Results. The analysis revealed systematic differences between radio-detected (i.e., radio-quiet), radio-intermediate, and RL classes in each spectral type along the main sequence. We show that spectral bins that contain the extreme Population A sources have radio power compatible with emission by mechanisms ultimately due to star formation processes. RL sources of Population B are characteristically jetted. Their broad Hβ profiles can be interpreted as due to a binary broad-line region. We suggest that RL Population B sources should be preferential targets for the search of black hole binaries, and present a sample of binary black hole AGN candidates. Conclusions. The validity of the Kellermann's criterion may be dependent on the source location along the quasar main sequence. The consideration of the main sequence trends allowed us to distinguish between sources whose radio emission mechanisms is jetted from the ones where the mechanism is likely to be fundamentally different. [ABSTRACT FROM AUTHOR]

By applying different statistically robust methods, we analyze the time lag between the continuum and ionized line‐emission (Mg II line) light curves for the distant bright quasar CTS C30.10 (redshift z∼0.9). The data were obtained by the 10‐meter South African Large Telescope (SALT) telescope in South Africa. In detail, we demonstrate the application of several methods using the interpolated cross‐correlation function (ICCF), discrete correlation function (DCF), z‐transformed discrete correlation function (zDCF), von Neumann estimator, and the JAVELIN code package. In particular, we discuss the uncertainties of these methods. In conclusion, we find that the quasar lies on the broad‐line region (BLR) size—monochromatic luminosity power‐law scaling, RBLR∝L51001/2, which was already confirmed for low‐redshift sources. In case, the BLR size–luminosity relation holds for other distant sources, quasars could be used to probe cosmological models as "standard candles" complementary to supernovae Ia. [ABSTRACT FROM AUTHOR]

Context. The analysis of the variability of active galactic nuclei (AGN) at different wavelengths and the study of possible correlations of different spectral windows are a current main field of inquiry. Optical variability has been largely used to identify AGN in multivisit surveys. The strength of a selection based on optical variability lies in the opportunity of analyzing data from surveys of large sky areas by ground-based telescopes. However, the effectiveness of optical variability selection with respect to other multiwavelength techniques has been poorly studied down to the depth that is expected from next-generation surveys. Aims. Here we present the results of our r-band analysis of a sample of 299 optically variable AGN candidates in the VST survey of the COSMOS field, counting 54 visits spread over three observing seasons spanning more than three years. This dataset is more than three times larger than the dataset presented in our previous analysis, and the observing baseline is about eight times longer. Methods. We push toward deeper magnitudes (r(AB) ∼ 23.5 mag) than were reached in past studies. We made wide use of ancillary multiwavelength catalogs in order to confirm the nature of our AGN candidates, and constrained the accuracy of the method based on spectroscopic and photometric diagnostics. We also performed tests aimed at assessing the relevance of dense sampling in view of future wide-field surveys. Results. We demonstrate that the method allows the selection of high-purity (> 86%) samples. We take advantage of the longer observing baseline to achieve great improvement in the completeness of our sample with respect to X-ray and spectroscopically confirmed samples of AGN (59% vs. ∼15% in our previous work), as well as in the completeness of unobscured and obscured AGN. The effectiveness of the method confirms the importance of developing future more refined techniques for the automated analysis of larger datasets. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The stellar initial mass function (IMF) regulates the baryonic cycle within galaxies, and is a key ingredient for translating observations into physical quantities. Although it was assumed to be universal for decades, there is now growing observational evidence showing that the center of massive early-type galaxies hosts a larger population of low-mass stars than is expected based on observations from the Milky Way. Moreover, these variations in the IMF have been found to be related to radial metallicity variations in massive galaxies. We present here a two-dimensional stellar population analysis of the massive lenticular galaxy FCC 167 (NGC 1380) as part of the Fornax3D project. Using a newly developed stellar population fitting scheme, we derive a full two-dimensional IMF map of an early-type galaxy. This two-dimensional analysis allows us go further than a radial analysis, showing how the metallicity changes along a disk-like structure while the IMF follows a distinct, less disky distribution. Thus, our findings indicate that metallicity cannot be the sole driver of the observed radial IMF variations. In addition, a comparison with the orbital decomposition shows suggestive evidence of a coupling between stellar population properties and the internal dynamical structure of FCC 167, where metallicity and IMF maps seem to track the distribution of cold and warm orbits, respectively. [ABSTRACT FROM AUTHOR]

This work presents the catalogue of optical spectral properties for all X-ray selected SPIDERS active galactic nuclei (AGN) up to SDSS DR14. SPIDERS (SPectroscopic IDentification of eROSITA Sources) is an SDSS-IV programme that is currently conducting optical spectroscopy of the counterparts to the X-ray selected sources detected in the ROSAT all-sky survey and the XMM-Newton slew survey in the footprint of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The SPIDERS DR14 sample is the largest sample of X-ray selected AGN with optical spectroscopic follow-up to date. The catalogue presented here is based on a clean sample of 7344 2RXS (z¯ = 0.5 z ¯ = 0.5 $ \bar{z}=0.5 $) and 1157 XMM-Newton slew survey (z¯ = 0.4 z ¯ = 0.4 $ \bar{z}=0.4 $) type 1 AGN with spectroscopic coverage of the Hβ and/or MgII emission lines. Visual inspection results for each object in this sample are available from a combination of literature sources and the SPIDERS group, which provide both reliable redshifts and source classifications. The spectral regions around the Hβ and MgII emission lines have been fit in order to measure both line and continuum properties, estimate bolometric luminosities, and provide black hole mass estimates using the single-epoch (or photoionisation) method. The use of both Hβ and MgII allows black hole masses to be estimated up to z ≃ 2.5. A comparison is made between the spectral properties and black hole mass estimates derived from Hβ and MgII using the subsample of objects which have coverage of both lines in their spectrum. These results have been made publicly available as an SDSS-IV DR14 value added catalogue. [ABSTRACT FROM AUTHOR]

Based on optical and near-IR Magellan FIRE spectra of 25 starburst galaxies at 0.5 <  z <  0.9, a recent publication showed that their attenuation properties can be explained by a single-parameter sequence of total obscurations ranging from AV = 2 to AV = 30 toward the starburst core centers in a mixed stars and dust configuration. We investigate here the origin of this sequence for the same sample. We show that total attenuations anticorrelate with the starburst sizes in radio (3 GHz) with a significance larger than 5σ and a scatter of 0.26 dex. More obscured and compact starbursts also show enhanced N2 (=[NII]/Hα) ratios and larger line velocity widths that we attribute to an increasing shock contribution toward later merger phases, driven by deeper gravitational potential wells at the coalescence. Additionally, the attenuation is also linked to the equivalent width (EW) of hydrogen recombination lines, which is sensitive to the luminosity weighted age of the relatively unobscured stellar populations. Overall, the correlations among AV, tot, radio size, line width, N2 and EW of Balmer and Paschen lines converge toward suggesting an evolutionary sequence of merger stages: all of these quantities are likely to be good time-tracers of the merger phenomenon, and their large spanned range appears to be characteristic of the different merger phases. Half of our sample at higher obscurations have radio sizes approximately 3 times smaller than early type galaxies at the same redshift, suggesting that, in analogy with local ultraluminous infrared galaxies (ULIRGs), these cores cannot be directly forming elliptical galaxies. Finally, we detect mid-IR AGN torus for half of our sample and additional X-ray emission for 6 starbursts; intriguingly, the latter have systematically more compact sizes, suggestive of emerging AGNs toward later merger stages, possibly precursors of a later QSO phase. [ABSTRACT FROM AUTHOR]

Context. Some Type-1 active galactic nuclei (AGN) show extremely asymmetric Balmer lines with the broad peak redshifted or blueshifted by thousands of km s−1. These AGN may be good candidates for supermassive binary black holes (SMBBHs). The complex line shapes can be due to the complex kinematics of the two broad line regions (BLRs). Therefore other methods should be applied to confirm the SMBBHs. One of them is spectropolarimetry. Aims. We rely on numerical modeling of the polarimetry of binary black holes systems, since polarimetry is highly sensitive to geometry, in order to find the specific influence of supermassive binary black hole (SMBBH) geometry and dynamics on polarized parameters across the broad line profiles. We apply our method to SMBBHs in which both components are assumed to be AGN with distances at the subparsec scale. Methods. We used a Monte Carlo radiative transfer code that simulates the geometry, dynamics, and emission pattern of a binary system where two black holes are getting increasingly close. Each gravitational well is accompanied by its own BLR and the whole system is surrounded by an accretion flow from the distant torus. We examined the emission line deformation and predicted the associated polarization that could be observed. Results. We modeled scattering-induced broad line polarization for various BLR geometries with complex kinematics. We find that the presence of SMBBHs can produce complex polarization angle profiles φ and strongly affect the polarized and unpolarized line profiles. Depending on the phase of the SMBBH, the resulting double-peaked emission lines either show red or blue peak dominance, or both the peaks can have the same intensity. In some cases, the whole line profile appears as a single Gaussian line, hiding the true nature of the source. Conclusions. Our results suggest that future observation with the high resolution spectropolarimetry of optical broad emission lines could play an important role in detecting subparsec SMBBHs. [ABSTRACT FROM AUTHOR]

Context. The innermost parts of powerful jets in active galactic nuclei are surrounded by dense, high-velocity clouds from the broad-line region, which may penetrate into the jet and lead to the formation of a strong shock. Such jet-cloud interactions are expected to have measurable effects on the γ-ray emission from blazars. Aims. We characterise the dynamics of a typical cloud-jet interaction scenario, and the evolution of its radiative output in the 0.1–30 GeV energy range, to assess to what extent these interactions can contribute to the γ-ray emission in blazars. Methods. We use semi-analytical descriptions of the jet-cloud dynamics, taking into account the expansion of the cloud inside the jet and its acceleration. Assuming that electrons are accelerated in the interaction and making use of the hydrodynamical information, we then compute the high-energy radiation from the cloud, including the absorption of γ-rays in the ambient photon field through pair creation. Results. Jet-cloud interactions can lead to significant γ-ray fluxes in blazars with a broad-line region (BLR), in particular when the cloud expansion and acceleration inside the jet are taken into account. This is caused by 1) the increased shocked area in the jet, which leads to an increase in the energy budget for the non-thermal emission; 2) a more efficient inverse Compton cooling with the boosted photon field of the BLR; and 3) an increased observer luminosity due to Doppler boosting effects. Conclusions. For typical broad-line region parameters, either (i) jet-cloud interactions contribute significantly to the persistent γ-ray emission from blazars or (ii) the BLR is far from spherical or the fraction of energy deposited in non-thermal electrons is small. [ABSTRACT FROM AUTHOR]

Context. A new generation of spectral synthesis models has been developed in recent years, but there is no matching set of template galaxy spectra, in terms of quality and resolution, for testing and refining the new models. Aims. Our main goal is to find and calibrate new near-infrared spectral indices along the Hubble sequence of galaxies which will be used to obtain additional constraints to the population analysis based on medium-resolution integrated spectra of galaxies. Methods. Spectra of previously studied and well-understood galaxies with relatively simple stellar populations (e.g., ellipticals or bulge dominated galaxies) are needed to provide a baseline data set for spectral synthesis models. Results. X-shooter spectra spanning the optical and infrared wavelengths (350–2400 nm) of bright nearby elliptical galaxies with a resolving power of R ∼ 4000–5400 were obtained. Heliocentric systemic velocity, velocity dispersion, and Mg, Fe, and Hβ line-strength indices are presented. Conclusions. We present a library of very-high-quality spectra of galaxies covering a large range of age, metallicity, and morphological type. Such a dataset of spectra will be crucial to addressing important questions of the modern investigation concerning galaxy formation and evolution. [ABSTRACT FROM AUTHOR]

Cosmic dust is a key tracer of structure formation and evolution in the universe. In active galactic nuclei (AGN) the origin and role of dust are uncertain. Here, we have studied dust in the X-ray bright and reddened type-1 quasar IC 4329A, which exhibits an ionised AGN wind. We incorporated high-resolution X-ray and mid-IR spectroscopy, combined with broad-band continuum modelling, to investigate the properties of dust in this AGN. We used new chandra HETGS observations taken in June 2017, as well as archival data from XMM-Newton, Swift, HST, Spitzer, IRAS, and Herschel for our IR-optical-UV-X-ray modelling. Two distinct components of dust in IC 4329A are found. One component is in the interstellar medium (ISM) of the host galaxy, and the other is a nuclear component in the AGN torus and its associated wind. The emitting dust in the torus is evident in mid-IR emission (9.7 and 18 μm features), while dust in the wind is present through both reddening and X-ray absorption (O, Si, and Fe edge features). The gas depletion factors into dust for O, Si, and Fe are measured. We derive an intrinsic reddening E(B – V) ≈ 1.0, which is most consistent with a grey (flat) extinction law. The AGN wind consists of three ionisation components. From analysis of long-term changes in the wind, we determine limits on the location of the wind components. The two lowest ionisation components are likely carriers of dust from the AGN torus. We find that the dust in the nuclear component of IC 4329A is different from dust in the Milky Way. The dust grains in the AGN torus and wind are likely larger than the standard Galactic dust, and are in a porous composite form (containing amorphous silicate with iron and oxygen). This can be a consequence of grain coagulation in the dense nuclear environment of the AGN. [ABSTRACT FROM AUTHOR]