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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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Reverberation Mapping of IC 4329A
Abstract We present the results of a new reverberation mapping campaign for the broad-line active galactic nucleus (AGN) in the edge-on spiral IC 4329A. Monitoring of the optical continuum with V- band photometry and broad emission-line flux variability with moderate-resolution spectroscopy allowed emission-line light curves to be measured for H β , H γ , and He ii λ 4686. We find a time delay of 16.3 − 2.3 + 2.6 days for H β , a similar time delay of 16.0 − 2.6 + 4.8 days for H γ , and an unresolved time delay of − 0.6 − 3.9 + 3.9 days for He ii . The time delay for H β is consistent with the predicted value from the relationship between AGN luminosity and broad-line region radius, after correction for the ∼2.4 mag of intrinsic extinction at 5100 Å. Combining the measured time delay for H β with the broad emission-line width and an adopted value of 〈 f 〉 = 4.8, we find a central supermassive black hole mass of M BH = 6.8 − 1.1 + 1.2 × 10 7 M ⊙ . Velocity-resolved time delays were measured across the broad H β emission-line profile and may be consistent with an “M”-like shape. Modeling of the full reverberation response of H β was able to provide only modest constraints on some parameters, but does exhibit agreement with the black hole mass and average time delay. The models also suggest that the AGN structure is misaligned by a large amount from the edge-on galaxy disk. This is consistent with expectations from the unified model of AGNs, in which broad emission lines are expected to be visible only for AGNs that are viewed at relatively face-on inclinations.
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- PAR ID:
- 10431688
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 944
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 29
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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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.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.3847/1538-4357/acab62
