Double tidal disruption events in the changing-look AGN Mrk1018

TL;DR

This paper presents evidence of double tidal disruption events in the changing-look AGN Mrk1018, explaining its long-term variability and linking TDEs to its changing spectral features.

Contribution

It introduces the concept of double TDEs in AGNs and demonstrates their role in explaining the variability of Mrk1018, a novel insight into AGN behavior.

Findings

Double TDEs can explain the 15-year light curve of Mrk1018.

The BH mass from double TDEs matches the M-sigma relation.

Double TDEs are linked to the changing-look phenomenon.

Abstract

Tidal disruption events (TDEs) as excellent beacons to black hole (BH) accreting systems have been studied for more than five decades with a single star tidally disrupted by a central massive BH. However, if considering two stars passing through a central BH and being tidally disrupted in a short period, so-called double TDEs could be expected and lead to unique variability features very different from features from standard TDEs. Here, we report such oversimplified double TDEs in the known changing-look AGN Mrk1018, of which 15years-long light curve with plateau features can be described by two main-sequence stars tidally disrupted by the central supermassive BH. Meanwhile, the BH mass determined by the double TDEs is consistent with the M-sigma relation determined value by the measured stellar velocity dispersions in Mrk1018. The results indicate tight connections between the TDEs and the changing-look properties in Mrk1018.