The Whisper and the Bang: Cosmic Fireworks in the Lives of Compact Binaries

Citation

De, Kishalay (2021) The Whisper and the Bang: Cosmic Fireworks in the Lives of Compact Binaries. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/vc3g-5723. https://resolver.caltech.edu/CaltechTHESIS:05062021-042641560

Abstract

Compact binaries, comprising of a white dwarf, neutron star or black hole in a tight orbit around another star are produced from binary evolution through a complex range of astrophysical processes -- ranging from eruptive mass loss episodes ('the whisper') to spectacular explosions ('the bang') that have shaped the universe as we see it today. In pursuit of a complete road-map of the explosive lives of high mass and low mass stars in compact binaries, I undertook two major experiments.

In the first two parts of this thesis, I describe the largest volume-limited supernova classification experiment undertaken till date, using the Zwicky Transient Facility optical time domain survey. I present the identification of a new class of 'ultra-stripped' supernovae that form neutron stars in compact binary systems, that are likely direct progenitors of merging neutron stars detectable in LIGO/Virgo. Using the systematic sample of supernovae, I identify a class of helium shell explosions on low mass white dwarfs that likely represent the final fates of helium accreting white dwarfs. In the third part of this thesis, I present the development of Palomar Gattini-IR (PGIR), the first wide-field infrared survey capable of studying the dynamic infrared sky from timescales of seconds to years. I present a systematic search for nova eruptions in the Milky Way using PGIR, and show that optical surveys have systematically missed a large fraction of dust obscured novae to derive the first quantitative estimate of the Galactic nova rate. I present the first infrared constraints on the second-timescale emission from a Galactic Fast Radio Burst identified with a dust obscured Galactic magnetar.

This thesis helps set the stage for a systematic exploration of the local stellar graveyard using i) the Vera Rubin Observatory to probe the lowest luminosity stellar deaths in the local universe and ii) the upcoming assemblage of infrared surveys to study variability in Galactic compact objects in conjunction with the rich landscape of X-ray and radio sky surveys. By mapping out the demographics of explosive phenomena, it helps us interpret the astrophysical populations detectable with current and future gravitational wave observatories.

Thesis Files