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1. 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)

   null (Ed.)

   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 γ 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. 

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2. Robotic reverberation mapping of the broad-line radio galaxy 3C 120

   https://doi.org/10.1093/mnras/staa2171  

   Hlabathe, Michael S; Starkey, David A; Horne, Keith; Romero-Colmenero, Encarni; Crawford, Steven M; Valenti, Stefano; Winkler, Hartmut; Barth, Aaron J; Onken, Christopher A; Sand, David J; et al (September 2020, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We carried out photometric and spectroscopic observations of the well-studied broad-line radio galaxy 3C 120 with the Las Cumbres Observatory (LCO) global robotic telescope network from 2016 December to 2018 April as part of the LCO AGN Key Project on Reverberation Mapping of Accretion Flows. Here, we present both spectroscopic and photometric reverberation mapping results. We used the interpolated cross-correlation function to perform multiple-line lag measurements in 3C 120. We find the H γ, He ii λ4686, H β, and He i λ5876 lags of $$\tau _{\text{cen}} = 18.8_{-1.0}^{+1.3}$$, $$2.7_{-0.8}^{+0.7}$$, $$21.2_{-1.0}^{+1.6}$$, and $$16.9_{-1.1}^{+0.9}$$ d, respectively, relative to the V-band continuum. Using the measured lag and rms velocity width of the H β emission line, we determine the mass of the black hole for 3C 120 to be $$M=(6.3^{+0.5}_{-0.3})\times 10^7\, (f/5.5)$$ M⊙. Our black hole mass measurement is consistent with similar previous studies on 3C 120, but with small uncertainties. In addition, velocity-resolved lags in 3C 120 show a symmetric pattern across the H β line, 25 d at line centre decreasing to 17 d in the line wings at ±4000 km s−1. We also investigate the inter-band continuum lags in 3C 120 and find that they are generally consistent with τ ∝ λ4/3 as predicted from a geometrically thin, optically thick accretion disc. From the continuum lags, we measure the best-fitting value τ0 = 3.5 ± 0.2 d at $$\lambda _{\rm 0} = 5477\, \mathring{\rm A}$$. It implies a disc size a factor of 1.6 times larger than prediction from the standard disc model with L/LEdd = 0.4. This is consistent with previous studies in which larger than expected disc sizes were measured. 

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3. Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns – I. Evolution of structure and kinematics

   https://doi.org/10.1093/mnras/stad051  

   Chen, Yong-Jie; Bao, Dong-Wei; Zhai, Shuo; Fang, Feng-Na; Hu, Chen; Du, Pu; Yang, Sen; Yao, Zhu-Heng; Li, Yan-Rong; Brotherton, Michael S; et al (February 2023, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We report the results of long-term reverberation mapping campaigns of the nearby active galactic nuclei (AGNs) NGC 4151, spanning from 1994 to 2022, based on archived observations of the FAST Spectrograph Publicly Archived Programs and our new observations with the 2.3 m telescope at the Wyoming Infrared Observatory. We reduce and calibrate all the spectra in a consistent way, and derive light curves of the broad H β line and 5100 Å continuum. Continuum light curves are also constructed using public archival photometric data to increase sampling cadences. We subtract the host galaxy contamination using Hubble Space Telescope imaging to correct fluxes of the calibrated light curves. Utilizing the long-term archival photometric data, we complete the absolute flux-calibration of the AGN continuum. We find that the H β time delays are correlated with the 5100 Å luminosities as $$\tau _{\rm H\beta }\propto L_{5100}^{0.46\pm 0.16}$$. This is remarkably consistent with Bentz et al. (2013)’s global size–luminosity relationship of AGNs. Moreover, the data sets for five of the seasons allow us to obtain the velocity-resolved delays of the H β line, showing diverse structures (outflows, inflows, and discs). Combining our results with previous independent measurements, we find the measured dynamics of the H β broad-line region (BLR) are possibly related to the long-term trend of the luminosity. There is also a possible additional ∼1.86 yr time lag between the variation in BLR radius and luminosity. These results suggest that dynamical changes in the BLR may be driven by the effects of radiation pressure. 

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4. 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)

   Abstract 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 of λ L λ (5100 Å) ≈ 10 44 erg s −1 and predicted H β lags of ∼20–30 days or black hole masses of 10 7 –10 8.5 M ⊙ , 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 H β emission-line light curves, integrated H β lag times (8–30 days) measured against V -band continuum light curves, velocity-resolved reverberation lags, line widths of the broad H β components, and virial black hole mass estimates (10 7.1 –10 8.1 M ⊙ ). 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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5. The spatially resolved broad line region of IRAS 09149−6206

   https://doi.org/10.1051/0004-6361/202039067  

   Amorim, A.; Bauböck, M.; Brandner, W.; Clénet, Y.; Davies, R.; de Zeeuw, P. T.; Dexter, J.; Eckart, A.; Eisenhauer, F.; Förster Schreiber, N. M.; et al (November 2020, Astronomy & Astrophysics)

   null (Ed.)

   We present new near-infrared VLTI/GRAVITY interferometric spectra that spatially resolve the broad Br γ 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  μ as (0.14 pc) between the BLR and the centroid of the hot dust distribution traced by the 2.3 μ m 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 Br γ line. We infer the radius of the BLR to be ∼65  μ as (0.075 pc), which is consistent with the radius–luminosity relation of nearby active galactic nuclei derived based on the time lag of the H β line from reverberation mapping campaigns. Our dynamical modelling indicates the black hole mass is ∼1 × 10 8   M ⊙ , which is a little below, but consistent with, the standard M BH – σ * relation. 

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