Constraints on black hole massess with timescales of variations in blazars

TL;DR

This paper presents a model linking black hole masses to minimum variability timescales in blazars, providing a new method to estimate black hole masses based on observed jet emission variations.

Contribution

The paper introduces a novel model that constrains black hole masses using minimum observed variability timescales in blazars, connecting jet emission dynamics with central black hole properties.

Findings

Estimated black hole masses are consistent with literature values.

Minimum variability timescales are on the order of hours.

Model successfully applied to 32 blazars, including gamma-ray detected sources.

Abstract

In this paper, we investigated the issue of black hole masses and minimum timescales of jet emission for blazars. We proposed a sophisticated model that sets an upper limit to the central black hole masses $M_{\bullet}$ with the minimum timescales $\Delta t^{\rm{ob}}_{\rm{min}}$ of variations observed in blazars. The value of $\Delta t^{\rm{ob}}_{\rm{min}}$ presents an upper limit to the size of blob in jet. The blob is assumed to be generated in the jet-production region in the vicinity of black hole, and then the expanding blob travels outward along the jet. We applied the model to 32 blazars, 29 of which were detected in gamma rays by satellites, and these $\Delta t^{\rm{ob}}_{\rm{min}}$ are on the order of hours with large variability amplitudes. In general, these $M_{\bullet}$ estimated with this method are not inconsistent with those masses reported in the literatures. This model is natural to connect $M_{\bullet}$ with $\Delta t^{\rm{ob}}_{\rm{min}}$ for blazars, and seems to be applicable to constrain $M_{\bullet}$ in the central engines of blazars.