Central BH mass of tidal disruption event candidate SDSS J0159 through long-term optical variabilities

In this manuscript, central BH mass is determined in the tidal disruption event (TDE) candidate SDSS J0159, through the nine years long variabilities, in order to check whether the virial BH mass is consistent with the mass estimated by another independent methods. First, host galaxy spectroscopic features are described by 350 simple stellar templates, to confirm the total stellar mass about $7\times10^{10}{\rm M_\odot}$ in SDSS J0159, indicating the virial BH mass about two magnitudes larger than the BH mass estimated by the total stellar mass. Second, based on an efficient method and fitting procedure, through theoretical TDE model applied to describe the SDSS $ugriz$-band light curves of SDSS J0159, central BH mass can be determined as $M_{BH}\sim4.5_{-1.1}^{+1.3}\times10^6{\rm M_\odot}$, well consistent with the M-sigma relation expected BH mass and the total stellar mass expected BH mass. Third, the theoretical TDE model with parameter of central BH mass limited to be higher than $10^8{\rm M_\odot}$ can not lead to reasonable descriptions to the light curves of SDSS J0159, indicating central BH mass higher than $10^8{\rm M_\odot}$ is not preferred in SDSS J0159. Therefore, the TDE model determined central BH mass of SDSS J0159 are about two magnitudes lower than the virial BH mass, to support central BLRs including accreting debris contributions from central TDE, and provide interesting clues to reconfirm that outliers in the space of virial BH mass versus stellar velocity dispersion should be better candidates of TDE.