Clues for the accretion regulated dust torus in the changing-look AGN SDSS J101152.98+544206.4

Abstract

Dust torus plays the key role in determining active galactic nuclei (AGN) observational appearance. Here, the scenario of accretion regulated central dust torus is tested for the first time in the individual changing-look AGN (CLAGN) SDSS J1011+5442. Through the dependence of broad H$\alpha$ luminosity on continuum luminosity, the scenario of moving dust clouds can be ruled out in SDSS J1011+5442. Meanwhile, virial BH mass in the bright state is consistent with the M-sigma relation determined mass, indicating the virialization assumptions efficient in central BLRs. However, the virial BH mass determined in the dim state is 60 times smaller than the M-sigma relation determined value. The contrary properties of broad H$\alpha$ in different states can be naturally explained by the scenario of accretion regulated dust torus. Below a critical Eddington ratio, opening angle of dust torus declines with increasing accretion rate, leading to only outer part of central BLRs for broad H$\alpha$ with smaller line widths detected in the dim state but all the BLRs detected in the bright state. The results in this manuscript not only indicate properties of central dust torus having apparent effects on variability properties of CLAGN, but also indicate that studying CLAGN could provide further clues to check dynamical evolving models for dust torus in AGN.