Simulations of Tidal Disruption of Supernova in Galaxy Nuclear Region: A Novel Model for Ambiguous Nuclear Transients

Abstract An increasing number of ambiguous nuclear transients, including some extreme nuclear transients with very shallow light-curve declines and weak active galactic nucleus (AGN) activity in their host galaxies, have been reported. Stars that form in or are captured by AGN disks will grow and migrate inward, potentially exploding as supernovae once the inner cold accretion disk disappears in low-luminosity AGNs. We propose that the tidal disruption of a supernova (TDS) by a supermassive black hole (SMBH) can produce nuclear transients that are more energetic and evolve more slowly than typical tidal disruption events (TDEs), without the black hole mass limit as in TDEs. In this scenario, the SMBH captures the supernova ejecta, which subsequently self-intersects and circularizes into an accretion disk. Based on hydrodynamical simulations, we find that the accretion rate of the TDS disk exhibits a slow decline that can last for months to decades. The peak accretion rate of a typical core-collapse supernova scenario can exceed the Eddington limit for SMBHs with M BH ≲ 10 7.5 M ⊙ , while it remains sub-Eddington for more massive SMBHs. This model provides a mechanism for triggering an energetic TDE-like flare with luminosity ≳10 45 erg s −1 in weak AGNs even with SMBH masses much larger than 10 8 M ⊙ or triggering turn-on changing-look AGNs.