We performed an intensive accretion disk reverberation mapping campaign on the high accretion rate active galactic nucleus Mrk 142 in early 2019. We measure significant time lags between the different wavelength lightcurves. In the UV and optical, we find that the wavelength-dependent lags, τ(λ), generally follow the relation τ(λ) ∝ λ4/3, as expected for the T ∝ R-3/4 profile of a steady-state, optically thick, geometrically thin accretion disk. The flux-flux analysis (shown in the figure) allowed us to separate the constant and variable components of the spectral energy distribution, finding that the flux dependence of the variable component is consistent with the fν ∝ ν1/3 spectrum expected for a geometrically thin accretion disk. The magnitude of the UV/optical lags is consistent with a highly super-Eddington accretion rate.
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 (ICCF) to perform multiple-line lag measurements in 3C 120. We find the Hγ, He II λ4686, Hβ and He I λ5876 lags. Using the measured lag and rms velocity width of the Hβ emission line, we determine the mass of the black hole for 3C 120 to be M = 6.3+0.5−0.3× 107( 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 Hβ line, 25 days at line centre decreasing to 17 days in the line wings at ±4000 km s−1.