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

   https://doi.org/10.3847/1538-4357/ac6171  

   Villafaña, Lizvette ; Williams, Peter R. ; Treu, Tommaso ; Brewer, Brendon J. ; Barth, Aaron J. ; U, Vivian ; Bennert, Vardha N. ; Alexander Vogler, H. ; Guo, Hengxiao ; Bentz, Misty C. ; et al ( May 2022 , The Astrophysical Journal)

   Abstract We have modeled the velocity-resolved reverberation response of the H β broad emission line in nine Seyfert 1 galaxies from the Lick Active Galactic Nucleus (AGN) Monitoring Project 2016 sample, drawing inferences on the geometry and structure of the low-ionization broad-line region (BLR) and the mass of the central supermassive black hole. Overall, we find that the H β BLR is generally a thick disk viewed at low to moderate inclination angles. We combine our sample with prior studies and investigate line-profile shape dependence, such as log 10 ( FWHM / σ ) , on BLR structure and kinematics and search for any BLR luminosity-dependent trends. We find marginal evidence for an anticorrelation between the profile shape of the broad H β emission line and the Eddington ratio, when using the rms spectrum. However, we do not find any luminosity-dependent trends, and conclude that AGNs have diverse BLR structure and kinematics, consistent with the hypothesis of transient AGN/BLR conditions rather than systematic trends.
2. 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.
3. Active Galactic Nuclei Continuum Reverberation Mapping Based on Zwicky Transient Facility Light Curves

   https://doi.org/10.3847/1538-4357/ac96ec  

   Guo, Hengxiao ; Barth, Aaron J. ; Wang, Shu ( November 2022 , The Astrophysical Journal)

   Abstract We perform a systematic survey of active galactic nuclei (AGNs) continuum lags using ∼3 days cadence gri -band light curves from the Zwicky Transient Facility. We select a sample of 94 type 1 AGNs at z < 0.8 with significant and consistent inter-band lags based on the interpolated cross-correlation function method and the Bayesian method JAVELIN . Within the framework of the “lamp-post” reprocessing model, our findings are: (1) The continuum emission (CE) sizes inferred from the data are larger than the disk sizes predicted by the standard thin-disk model. (2) For a subset of the sample, the CE size exceeds the theoretical limit of the self-gravity radius (12 lt-days) for geometrically thin disks. (3) The CE size scales with continuum luminosity as R CE ∝ L 0.48±0.04 with a scatter of 0.2 dex, analogous to the well-known radius–luminosity relation of broad H β . These findings suggest a significant contribution of diffuse continuum emission from the broad-line region (BLR) to AGN continuum lags. We find that the R CE – L relation can be explained by a photoionization model that assumes ∼23% of the total flux comes from the diffuse BLR emission. In addition, the ratio of themore »CE size and model-predicted disk size anticorrelates with the continuum luminosity, which is indicative of a potential nondisk BLR lag contribution evolving with the luminosity. Finally, a robust positive correlation between the CE size and black hole mass is detected.« less
4. Influence of Comptonization region over the ambiance of accretion disc in active galactic nucleus

   https://doi.org/10.1093/mnras/stab3610  

   Sriram, K. ; Nour, D. ; Choi, C. S. ( December 2021 , Monthly Notices of the Royal Astronomical Society)

   Understanding the radiative and physical structures of inner region of a few 100 pc of active galactic nucleus (AGNs) is important to constrain the causes of their activities. Although the X-ray emission from the Comptonization region/corona and the accretion disc regulates the broad-line emission regions and torus structures, the exact mutual dependency is not understood well. We performed correlation studies for X-ray, mid-infrared, and different components of Balmer emission lines for the selected sample of AGNs. Almost 10 different parameters and their interdependencies were explored in order to understand the underlying astrophysics. We found that the X-ray luminosity has a linear dependency on the various components of broad Balmer emission lines (e.g. L$_{\text{2-10 keV}}\, \propto$ L$^{0.78}_{\text{H}\beta ^{\text{B}}}$) and found a strong dependency on the optical continuum luminosity (L$_{\text{2-10 keV}}\, \propto$ L$^{0.86}_{5100\, \mathring{\rm A}}$). For a selected sample, we also observed a linear dependency between X-ray and mid-infrared luminosity (L$_{\text{2-10 keV}}\, \propto$ L$^{0.74}_{6\, \mu \text{m}}$). A break point was observed in our correlation studies for X-ray power-law index, Γ, and mass of black hole at ∼ log (M/M⊙)  = 8.95. Similarly, the relations between Γ and full width at half-maximum (FWHM) of H α and H β broad components show breaks at FWHMH α = 7642 ± 657 km s−1more »and FWHMH β  = 7336 ± 650 km s−1. However, more data are required to confine the breaks locations exactly. We noted that Γ and Eddington ratios are negatively correlated to Balmer decrements in our selected sample. We analysed and discussed about the implications of new findings in terms of interaction AGN structures.

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5. The central parsec of NGC 3783: a rotating broad emission line region, asymmetric hot dust structure, and compact coronal line region

   https://doi.org/10.1051/0004-6361/202040061  

   Amorim, A. ; Bauböck, M. ; Brandner, W. ; Bolzer, M. ; Clénet, Y. ; Davies, R. ; de Zeeuw, P. T. ; Dexter, J. ; Drescher, A. ; Eckart, A. ; et al ( April 2021 , Astronomy & Astrophysics)

   Using VLTI/GRAVITY and SINFONI data, we investigate the subparsec gas and dust structure around the nearby type 1 active galactic nucleus (AGN) hosted by NGC 3783. The K -band coverage of GRAVITY uniquely allows simultaneous analysis of the size and kinematics of the broad line region (BLR), the size and structure of the near-infrared(near-IR)-continuum-emitting hot dust, and the size of the coronal line region (CLR). We find the BLR, probed through broad Br γ emission, to be well described by a rotating, thick disc with a radial distribution of clouds peaking in the inner region. In our BLR model, the physical mean radius of 16 light-days is nearly twice the ten-day time-lag that would be measured, which closely matches the ten-day time-lag that has been measured by reverberation mapping. We measure a hot dust full-width at half-maximum (FWHM) size of 0.74 mas (0.14 pc) and further reconstruct an image of the hot dust, which reveals a faint (5% of the total flux) offset cloud that we interpret as an accreting or outflowing cloud heated by the central AGN. Finally, we directly measure the FWHM size of the nuclear CLR as traced by the [Ca  VIII ] and narrow Br γmore »line. We find a FWHM size of 2.2 mas (0.4 pc), fully in line with the expectation of the CLR located between the BLR and narrow line region. Combining all of these measurements together with larger scale near-IR integral field unit and mid-IR interferometry data, we are able to comprehensively map the structure and dynamics of gas and dust from 0.01 to 100 pc.« less