Estimation of the size and structure of the broad line region using Bayesian approach

Abstract

Understanding the geometry and kinematics of the broad line region (BLR) of active galactic nuclei (AGN) is important to estimate black hole masses in AGN and study the accretion process. The technique of reverberation mapping (RM) has provided estimates of BLR size for more than 100 AGN now, however, the structure of the BLR has been studied for only a handful number of objects. Towards this, we investigated the geometry of the BLR for a large sample of 57 AGN using archival RM data. We performed systematic modeling of the continuum and emission line light curves using a Markov Chain Monte Carlo method based on Bayesian statistics implemented in PBMAP (Parallel Bayesian code for reverberation-MAPping data) code to constrain BLR geometrical parameters and recover velocity integrated transfer function. We found that the recovered transfer functions have various shapes such as single-peaked, double-peaked and top-hat suggesting that AGN have very different BLR geometries. Our model lags are in general consistent with that estimated using the conventional cross-correlation methods. The BLR sizes obtained from our modeling approach is related to the luminosity with a slope of 0.583 (+/-) 0.026 and 0.471 (+/-) 0.084 based on Hβ and Hα lines, respectively. We found a non-linear response of emission line fluxes to the ionizing optical continuum for 93\% objects. The estimated virial factors for the AGN studied in this work range from 0.79 to 4.94 having a mean at 1.78 (+/-) 1.77 consistent with the values found in the literature.

20 pages, 16 figures, 5 tables, Accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS), 30 December 2020

References in corpus (19)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• The AGN Black Hole Mass Database
• The black hole mass - stellar velocity dispersion relation of narrow-line Seyfert 1 galaxies
• Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies
• The Black Hole Mass Scale of Classical and Pseudo Bulges in Active Galaxies
• Supermassive black holes with high accretion rates in active galactic nuclei: II. the most luminous standard candles in the Universe
• The effect of nuclear gas distribution on the mass determination of supermassive black holes
• Limitations on the recovery of the true AGN variability parameters using Damped Random Walk modeling
• Reverberation Mapping of the Seyfert 1 Galaxy NGC 7469
• The Mass of the Central Black Hole in the Nearby Seyfert Galaxy NGC5273
• X-ray flux variability of active galactic nuclei observed using NuSTAR
• Supermassive black holes with high accretion rates in active galactic nuclei: X. Optical variability characteristics
• MgII Line Variability of High Luminosity Quasars
• Differential interferometry of QSO broad line regions I: improving the reverberation mapping model fits and black hole mass estimates
• A Method to Measure the Unbiased Decorrelation Timescale of the AGN Variable Signal from Structure Functions
• Time Series Analysis of Active Galactic Nuclei: The case of Arp 102B, 3C 390.3, NGC 5548 and NGC 4051
• Imaging the AGN Torus in Cygnus
• Relation between the variations in the MgII $\lambda 2798$ emission-line and the 3000 Å continuum
• Dust Reverberation Mapping of Z229-15

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