A candidate for central tidal disruption event in the broad line AGN SDSS J1605 with double-peaked broad H β

Abstract

ABSTRACT In this letter, motivated by double-peaked broad Balmer emission lines probably related to tidal disruption events (TDEs), a potential TDE candidate is reported in Sloan Digital Sky Survey (SDSS) J160536+134838 (=SDSS J1605) at z ∼ 0.44 having quasar-like spectrum but with double-peaked broad H β. The long-term Catalina Sky Survey (CSS) light curve can be naturally described by a main-sequence star of $2.82_{-0.19}^{+0.20}{\rm M_\odot }$ disrupted by the central black hole (BH) of $144_{-21}^{+26} \times 10^6{\rm M_\odot }$ in SDSS J1605. Meanwhile, the All-Sky Automated Survey for SuperNovae light curves afterwards show none apparent trend variability, indicating the bright CSS flare in SDSS J1605 unique and different enough from variability of normal active galactic nuclei (AGN). Furthermore, there is a consistency between the TDE model determined sizes of debris with the sizes of emission regions for the double-peaked broad H β described by the accretion disc model, supporting the disc-like broad emission line regions (BLRs) probably related to a central TDE in SDSS J1605. And the virial BH mass ∼7 times higher than the TDE model determined value can be naturally explained by R–L relation determined BLRs sizes very larger than the actual distance of emission regions related to TDEs debris in SDSS J1605. Although no clear conclusion on double-peaked broad lines absolutely related to TDEs, the results here provide clues to detect potential TDEs in AGN with double-peaked broad lines.