HEAT mtg: Paarmita Pandey, Ohio State

Unraveling the Nature of the Nuclear Transient AT2020adpi

Paarmita Pandey, Ohio State

Abstract: Transient events associated with supermassive black holes (SMBHs) offer rare glimpses into accretion physics and the dynamic environments of galactic nuclei. In this talk, I will present a comprehensive multiwavelength study of AT2020adpi (ZTF20acvfraq), a luminous optical/UV transient at z = 0.26 that exhibits characteristics of an ambiguous nuclear transient (ANT), which are a new and emerging class of events with properties that are different from both tidal disruption events (TDEs) and standard active galactic nuclei (AGN) variability. I will discuss the temporal and spectral evolution of AT2020adpi, its host galaxy properties, and how it compares to other nuclear transients in the broader luminosity–timescale phase space. The transient’s peculiar light curve, strong MIR flare, and evolving emission-line features point toward an accretion episode possibly triggered by a stellar disruption within an existing accretion disk, or by instabilities in an active nucleus. AT2020adpi highlights the challenges of classifying nuclear transients and the need for coordinated, multiwavelength monitoring to disentangle AGN variability from tidal disruption signatures.

Host: Jillian Chin Rastinejad