# # Program information file # PROGRAM_ID 2024A083 PROGRAM_TITLE SpeX spectroscopy of luminous infrared echoes of extreme accretion phenomena PROGRAM_INV1 Megan Masterson PROGRAM_INV2 Kishalay De PROGRAM_INV3 Christos Panagiotou PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT extra-galactic PROGRAM_ABSTRACT_BEG Accretion onto supermassive black holes is now being revealed to be much more violent and rapidly variable than previously thought -- with the discovery of extreme accretion phenomena such as Tidal disruption events and changing look AGN. Yet conventional discovery methods in the optical/X-ray bands are blind to events occurring in extremely dusty environments expected in the centers of galaxies, leaving a gaping hole in our understanding of their demographics. With its long baseline and infrared sensitivity, the NEOWISE time domain data set offers the ability to search for these missed events via their luminous dust echoes. While previous works have attempted to search for these events, they remain incomplete due to their target selection strategies or detection methods. A sample of luminous IR flares coincident with known galaxies have recently been identified using a novel image subtraction pipeline to detect transients directly in NEOWISE data. Here, we request IRTF/SpeX spectroscopy of a sample of the most luminous flares. The NIR spectra, uniquely attainable with the infrared capabilities and superior seeing at Mauna Kea, will reveal signatures of accretion via the prominent H, He, O and coronal lines in the NIR band [where dust obscuration is less effective], allowing direct confirmation and characterization of the accretion flow. Together with archival information on the sources, the program will reveal demographics of a previously overlooked method for discovering extreme accretion phenomena. PROGRAM_ABSTRACT_END