Modeling the flare in NGC 1097 from 1991 to 2004 as a tidal disruption event

TL;DR

This study models the 13-year variability of NGC 1097's broad Hα emission as a tidal disruption event, supporting TDE as a cause for double-peaked lines and changing-look AGN phenomena.

Contribution

It provides the first detailed modeling linking a long-term emission line variability in NGC 1097 to a TDE, estimating the disrupted star's mass and the black hole's mass.

Findings

TDE model accurately predicts the 13-year Hα flux variability.

Estimated disrupted star mass is 1-1.5 solar masses.

Black hole mass in NGC 1097 is about 5-8×10^7 solar masses.

Abstract

In the Letter, interesting evidence is reported to support a central tidal disruption event (TDE) in the known AGN NGC 1097. Considering the motivations of TDE as one probable origination of emission materials of double-peaked broad emission lines and also as one probable explanation to changing-look AGN, it is interesting to check whether are there clues to support a TDE in NGC 1097, not only a changing-look AGN but also an AGN with double-peaked broad emission lines. Under the assumption that the onset of broad H$\alpha$ emission was due to a TDE, the 13years-long (1991-2004) variability of double-peaked broad H$\alpha$ line flux in NGC 1097 can be well predicted by theoretical TDE model, with a $(1-1.5){\rm M_\odot}$ main-sequence star tidally disrupted by the central BH with TDE model determined mass about $(5-8)\times10^7{\rm M_\odot}$. The results provide interesting evidence to not only support TDE-related origin of double-peaked broad line emission materials but also support TDE as an accepted physical explanation to physical properties of changing-look AGN.