Cake Talk by Thomas Reynolds

A tidal disruption event (TDE) occurs when a star is torn apart by the tidal forces close to a supermassive black hole (SMBH) and much of the stellar material is accreted. A number of TDEs discovered at optical wavelengths have been associated with infrared (IR) emission in excess of their hot UV+optical blackbody. This IR echo arises from dust that lies in the proximity of the SMBH which absorbs the UV emission from the TDE and re-radiates this energy in the IR. Observed IR echoes have typically been much less luminous than the UV+optical emission arising from the TDE, indicating a relatively dust-free environment. In this talk I will discuss a population of IR transients discovered in luminous and ultraluminous infrared galaxies (U/LIRGs) that exhibit extremely large radiated energies in the IR but are obscured in the optical. These transients are characterised through multi-wavelength observations and found to be consistent with a population of TDEs that are inaccessible to optical surveys. Through fitting of the spectral energy distribution of their host galaxies we find that the transients occur within Type 2 active galactic nuclei, and this environment can explain the properties of the observed transients. Our rate of discovery of these transients indicates that the TDE rate within LIRGs is 1-2 orders of magnitude higher than in typical galaxies, consistent with their status as merging galaxy systems with high star formation rates. Finally, I will briefly discuss an ongoing survey to detect and better characterise the IR echoes from optically discovered TDEs.