astrolunch: Kishalay De (Caltech)

Wed, 12/05/2021
Title: The explosive lives and fates of accreting white dwarfs in wide-field time domain surveys

Abstract: The lives and fates of accreting white dwarfs are crucial for a broad range of issues in modern astrophysics -- ranging from the progenitors of Type Ia supernovae to the loudest gravitational wave sources detectable by LISA. In this talk, I will discuss new insights into the rich diversity of explosive phenomena from accreting white dwarfs in novel time domain surveys. Helium accreting white dwarfs have been long proposed as sub-Chandrasekhar mass progenitors of Type Ia supernovae, although models have had difficulties in explaining their observational properties. I will present new observational evidence for a class of helium shell explosions on low mass white dwarfs uncovered with the Zwicky Transient Facility optical survey -- ranging from peculiar Type Ia supernovae to the faintest class of 'Ca-rich' transients. I will discuss the development of the first wide-field infrared time domain survey called Palomar Gattini-IR. By scanning the entire sky every two nights, Palomar Gattini-IR is uncovering optically obscured phenomena in our own Galaxy, and providing new clues to the classical nova rate in the Milky Way as well as the dynamic 'stable' fates of merging white dwarfs.