Astronomy Colloquium - Michael Tucker

It is an exciting time for time-domain astronomy. The proliferation of sky surveys (ASAS-SN, Pan-STARRS, ZTF) has revolutionized our view of the eruptive and explosive occurring in the Universe. These surveys find more than 10,000 supernovae per year combined, requiring a paradigm shift in how we select the few objects worth detailed study. The first part of my talk will describe our brute-force approach to this problem with the Spectroscopic Classification of Astronomical Transients survey, including the most interesting discoveries from our first 5 years of operations. Next, I will discuss the long-sought progenitors of Type Ia supernovae. These events are best known for their role as extragalactic standard(izable) candles and remain a core pillar of modern cosmology, yet we still do not understand how a white dwarf reaches the necessary conditions for core carbon ignition (temperature ~few billion Kelvin, density ~few billion g/cm3). I will summarize the current observational constraints on candidate progenitor systems and present new evidence for merging white dwarf binaries producing some, but not all, of these cosmic explosions. Finally, I will conclude by looking to the (immediate) future with Rubin Observatory/LSST which will play an outsized role in time-domain astronomy over the next decade, although perhaps not in the ways you expect.s.