A Polarimetric Method for Measuring Black Hole Masses in Active Galactic Nuclei

TL;DR

This paper introduces a polarimetric method to estimate supermassive black hole masses in active galactic nuclei by analyzing the polarization of broad emission lines, accounting for the BLR's flattened geometry.

Contribution

It presents a novel approach linking spectropolarimetric data with the virial theorem to directly measure SMBH masses considering BLR geometry.

Findings

New SMBH mass estimates for AGN with polarization data

Determination of the virial coefficient from polarimetric observations

Validation of the flattened BLR model through polarization analysis

Abstract

The structure of the broad emission line region (BLR) in active galactic nuclei (AGN) remains unclear. We test in this paper a flattened configuration model for BLR. The virial theorem, by taking into account the disc shape of BLR, allows us to get a direct connection between the mass of a supermassive black hole (SMBH) and the inclination angle of the accretion flow. The inclination angle itself is derived from the spectropolarimetric data on broad emission lines using the theory for the generation of polarized radiation developed by Sobolev and Chandrasekhar. As the result, the new estimates of SMBH masses in AGN with measured polarization of BLR are presented. It is crucial that the polarimetric data allow also to determine the value of the virial coefficient that is essential for determining SMBH masses.