On the Systematic Bias in the Estimation of Black Hole Masses in Active Galactic Nuclei

TL;DR

This paper investigates biases in black hole mass estimates in active galactic nuclei, demonstrating that a revised formalism reduces discrepancies and highlights the multi-component nature of broad-line regions.

Contribution

It shows that the Wang et al. (2009) formalism provides more consistent black hole mass estimates and emphasizes the importance of correcting for line profile contributions.

Findings

Wang et al. (2009) formalism aligns better with math- ext{sigma}_* relation

Line profile analysis reveals multi-component broad-line regions

Wing contributions bias single-epoch mass estimators

Abstract

In this report, we find the \mbh estimated from the formalism of Wang et al. (2009)[1] are more consistent with those from the \mbh-$\sigma_*$ relation than those from previous single-epoch mass estimators, using a large sample of AGNs. Furthermore, we examine the differences between the line widths of \hb and \mgii in detail by comparing their line profiles. The flux around the line core and that in the wing of both \hb and \mgii show an opposite variation tendency, which indicates the BLR is multi-componential. The contribution of the wing makes the FWHM deviate from $\sigma_{line}$, and thus bias the \mbh estimated from previous single-epoch mass estimators. Thus the correction on the formalism suggested by Wang et al. (2009)[1] is crucial to \mbh estimation.