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1. The Lick AGN Monitoring Project 2016: Velocity-resolved Hβ Lags in Luminous Seyfert Galaxies

   https://doi.org/10.3847/1538-4357/ac3d26  

   U, Vivian ; Barth, Aaron J. ; Vogler, H. Alexander ; Guo, Hengxiao ; Treu, Tommaso ; Bennert, Vardha N. ; Canalizo, Gabriela ; Filippenko, Alexei V. ; Gates, Elinor ; Hamann, Frederick ; et al ( January 2022 , The Astrophysical Journal)

   We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to 2017 May. Targeting active galactic nuclei (AGNs) with luminosities ofλL_λ(5100 Å) ≈ 10⁴⁴erg s⁻¹and predicted Hβlags of ∼20–30 days or black hole masses of 10⁷–10^8.5M_⊙, our campaign probes luminosity-dependent trends in broad-line region (BLR) structure and dynamics as well as to improve calibrations for single-epoch estimates of quasar black hole masses. Here we present the first results from the campaign, including Hβemission-line light curves, integrated Hβlag times (8–30 days) measured againstV-band continuum light curves, velocity-resolved reverberation lags, line widths of the broad Hβcomponents, and virial black hole mass estimates (10^7.1–10^8.1M_⊙). Our results add significantly to the number of existing velocity-resolved lag measurements and reveal a diversity of BLR gas kinematics at moderately high AGN luminosities. AGN continuum luminosity appears not to be correlated with the type of kinematics that its BLR gas may exhibit. Follow-up direct modeling of this data set will elucidate the detailed kinematics and provide robust dynamical black hole masses for several objects in this sample.

    

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2. What Does the Geometry of the Hβ BLR Depend On?

   https://doi.org/10.3847/1538-4357/accc84  

   Villafaña, Lizvette ; Williams, Peter R. ; Treu, Tommaso ; Brewer, Brendon J. ; Barth, Aaron J. ; U, Vivian ; Bennert, Vardha N. ; Guo, Hengxiao ; Bentz, Misty C. ; Canalizo, Gabriela ; et al ( May 2023 , The Astrophysical Journal)

   We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors,f, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (caramel) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations betweenfand other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient${\log }_{10}(f_{\mathrm{mean},\sigma })$and black-hole mass, (ii) marginal evidence for a similar correlation between${\log }_{10}(f_{\mathrm{rms},\sigma })$and black-hole mass, (iii) marginal evidence for an anticorrelation of BLR disk thickness with${\log }_{10}(f_{\mathrm{mean},\mathrm{FWHM}})$and${\log }_{10}(f_{\mathrm{rms},\mathrm{FWHM}})$, and (iv) marginal evidence for an anticorrelation of inclination angle with${\log }_{10}(f_{\mathrm{mean},\mathrm{FWHM}})$,${\log }_{10}(f_{\mathrm{rms},\sigma })$, and${\log }_{10}(f_{\mathrm{mean},\sigma })$. Last, we find marginal evidence for a correlation between line-profile shape, when using the root-mean-square spectrum,${\log }_{10}{(\mathrm{FWHM}/\sigma )}_{\mathrm{rms}}$, and the virial coefficient,${\log }_{10}(f_{\mathrm{rms},\sigma })$, and investigate how BLR properties might be related to line-profile shape usingcaramelmodels.

    

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3. The Seoul National University AGN Monitoring Project. IV. Hα Reverberation Mapping of Six AGNs and the Hα Size–Luminosity Relation

   https://doi.org/10.3847/1538-4357/ace1e5  

   Cho, Hojin ; Woo, Jong-Hak ; Wang, Shu ; Son, Donghoon ; Shin, Jaejin ; Rakshit, Suvendu ; Barth, Aaron J. ; Bennert, Vardha N. ; Gallo, Elena ; Hodges-Kluck, Edmund ; et al ( August 2023 , The Astrophysical Journal)

   The broad-line region (BLR) size–luminosity relation has paramount importance for estimating the mass of black holes in active galactic nuclei (AGNs). Traditionally, the size of the HβBLR is often estimated from the optical continuum luminosity at 5100 Å, while the size of the HαBLR and its correlation with the luminosity is much less constrained. As a part of the Seoul National University AGN Monitoring Project, which provides 6 yr photometric and spectroscopic monitoring data, we present our measurements of the Hαlags of high-luminosity AGNs. Combined with the measurements for 42 AGNs from the literature, we derive the size–luminosity relations of the HαBLR against the broad Hαand 5100 Å continuum luminosities. We find the slope of the relations to be 0.61 ± 0.04 and 0.59 ± 0.04, respectively, which are consistent with the Hβsize–luminosity relation. Moreover, we find a linear relation between the 5100 Å continuum luminosity and the broad Hαluminosity across 7 orders of magnitude. Using these results, we propose a new virial mass estimator based on the Hαbroad emission line, finding that the previous mass estimates based on scaling relations in the literature are overestimated by up to 0.7 dex at masses lower than 10⁷M_⊙.

    

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4. Toward measuring supermassive black hole masses with interferometric observations of the dust continuum

   https://doi.org/10.1051/0004-6361/202244655  

   Amorim, A. ; Bourdarot, G. ; Brandner, W. ; Cao, Y. ; Clénet, Y. ; Davies, R. ; de Zeeuw, P. T. ; Dexter, J. ; Drescher, A. ; Eckart, A. ; et al ( January 2023 , Astronomy & Astrophysics)

   This work focuses on active galactic nuclei (AGNs) and on the relation between the sizes of the hot dust continuum and the broad-line region (BLR). We find that the continuum size measured using optical/near-infrared interferometry (OI) is roughly twice that measured by reverberation mapping (RM). Both OI and RM continuum sizes show a tight relation with the H β BLR size, with only an intrinsic scatter of 0.25 dex. The masses of supermassive black holes (BHs) can hence simply be derived from a dust size in combination with a broad line width and virial factor. Since the primary uncertainty of these BH masses comes from the virial factor, the accuracy of the continuum-based BH masses is close to those based on the RM measurement of the broad emission line. Moreover, the necessary continuum measurements can be obtained on a much shorter timescale than those required monitoring for RM, and they are also more time efficient than those needed to resolve the BLR with OI. The primary goal of this work is to demonstrate a measuring of the BH mass based on the dust-continuum size with our first calibration of the R BLR – R d relation. The current limitation and caveats are discussed in detail. Future GRAVITY observations are expected to improve the continuum-based method and have the potential of measuring BH masses for a large sample of AGNs in the low-redshift Universe. 

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5. Modelling the AGN broad-line region using single-epoch spectra − II. Nearby AGNs

   https://doi.org/10.1093/mnras/staa285  

   Raimundo, S I ; Vestergaard, M ; Goad, M R ; Grier, C J ; Williams, P R ; Peterson, B M ; Treu, T ( March 2020 , Monthly Notices of the Royal Astronomical Society)

   ABSTRACT 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. 

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