Using simultaneous modeling of continuum lag-spectrum and broadband SED of Fairall 9 with the H0RIZON-AGN model, the authors obtain H0 = 72.4_{-3.7}^{+3.4} km s^{-1} Mpc^{-1}.
Is Quasar Optical Variability a Damped Random Walk?
5 Pith papers cite this work. Polarity classification is still indexing.
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abstract
The damped random walk (DRW) model is increasingly used to model the variability in quasar optical light curves, but it is still uncertain whether the DRW model provides an adequate description of quasar optical variability across all time scales. Using a sample of OGLE quasar light curves, we consider four modifications to the DRW model by introducing additional parameters into the covariance function to search for deviations from the DRW model on both short and long time scales. We find good agreement with the DRW model on time scales that are well sampled by the data (from a month to a few years), possibly with some intrinsic scatter in the additional parameters, but this conclusion depends on the statistical test employed and is sensitive to whether the estimates of the photometric errors are correct to within ~10%. On very short time scales (below a few months), we see some evidence of the existence of a cutoff below which the correlation is stronger than the DRW model, echoing the recent finding of Mushotzky et al. (2011) using quasar light curves from Kepler. On very long time scales (> a few years), the light curves do not constrain models well, but are consistent with the DRW model.
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XRISM multi-epoch spectra of NGC 4151 yield a 3.5-day lag in the narrow Fe Kα line flux, consistent with a broad-line-region origin and giving M_BH/f_X ≈ 2×10^7 solar masses.
Non-detections of expected third flares in TDE 2022dbl and TDE 2020vdq support rpTDE interpretation over independent events, with modeling favoring bound main-sequence star orbits and deep initial encounters.
Simultaneous observations of NGC 4151 and UGC 3374 show that ICCF-Cut photometric Hα light curves and lags match spectroscopic results within uncertainties, with minor discrepancies attributed to He I contamination that can be corrected.
Bayesian fitting of an eccentric Keplerian orbit to the radio light curve of PKS 2131-021 gives e = 0.053 ± 0.015 without red noise but favors a circular orbit plus DRW noise with e < 0.15.
citing papers explorer
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HALO II: Constraining Hubble constant $H_{0}$ through continuum delay fitting of Fairall 9
Using simultaneous modeling of continuum lag-spectrum and broadband SED of Fairall 9 with the H0RIZON-AGN model, the authors obtain H0 = 72.4_{-3.7}^{+3.4} km s^{-1} Mpc^{-1}.
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Reverberation in the Narrow Fe K${\alpha}$ Line in the Seyfert Galaxy NGC 4151 with XRISM
XRISM multi-epoch spectra of NGC 4151 yield a 3.5-day lag in the narrow Fe Kα line flux, consistent with a broad-line-region origin and giving M_BH/f_X ≈ 2×10^7 solar masses.
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A Disappearing Act: Constraints From "Missing" Flares of Repeating Partial TDE Candidates
Non-detections of expected third flares in TDE 2022dbl and TDE 2020vdq support rpTDE interpretation over independent events, with modeling favoring bound main-sequence star orbits and deep initial encounters.
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Validating the ICCF-Cut Method with Simultaneous Photometric and Spectroscopic H$\alpha$ Reverberation Mapping of NGC 4151 and UGC 3374
Simultaneous observations of NGC 4151 and UGC 3374 show that ICCF-Cut photometric Hα light curves and lags match spectroscopic results within uncertainties, with minor discrepancies attributed to He I contamination that can be corrected.
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Constraining Orbital Eccentricity of a Supermassive Black Hole Binary Candidate PKS 2131-0211
Bayesian fitting of an eccentric Keplerian orbit to the radio light curve of PKS 2131-021 gives e = 0.053 ± 0.015 without red noise but favors a circular orbit plus DRW noise with e < 0.15.