Spectral Properties of NGC 4151 and the Estimation of Black Hole Mass Using TCAF Solution

• Published in: The Astrophysical journal Vol. 877; no. 2; pp. 65 - 71
• Main Authors: Nandi, Prantik, Chakrabarti, Sandip K., Mondal, Santanu
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.06.2019; IOP Publishing
• Subjects: Accretion; Accretion disks; accretion, accretion disks; Active galactic nuclei; Advective flow; Angular momentum; Astrophysics; Black holes; Continuum radiation; Flow geometry; galaxies: active; galaxies: individual (NGC 4151); galaxies: Seyfert; hydrodynamics; Kinematics; Mapping; Physical properties; Power law; Seyfert galaxies; shock waves; Spectral analysis; Spectrum analysis; Supermassive black holes; X ray spectra
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ab1d62

We present X-ray spectral analysis of Seyfert 1.5 Active Galactic Nuclei (AGNs) NGC 4151 using NuSTAR observations during 2012. This is the first attempt to fit AGN data using the physical Two Component Advective flow (TCAF) solution. We disentangle the continuum emission properties of the source in the energy range 3.0-70.0 keV using the spectrum obtained from the TCAF model. This model was used as an additive local model directly in XSPEC. Additionally, we used a power-law component, to take care of possible X-ray contribution from the jet, which is not incorporated in the present version of TCAF. Our primary aim is to obtain the flow properties and the mass of the central supermassive black hole from the available archival data. Our best estimate of the average mass obtained from spectral fits of three observations is MBH = 3.03+0.26−0.26 × 107 M . This is consistent with earlier estimations in the literature such as reverberation mapping, gas kinematics, and stellar dynamics around black holes. We also discuss the accretion dynamics and the flow geometry on the basis of model-fitted physical parameters. Model-fitted disk accretion rate is found to be lower than the low angular momentum halo accretion rate, indicating that the source was in a hard state during the observation.