Abstract

In the last few years, the discovery of cosmic explosions has become routine: every night, robotic optical telescopes mosaic the sky with a time resolution of minutes to days and identify 10^5 candidate new transients. In my talk, I will illustrate how to sift through the transient deluge with well-defined criteria and conduct prompt follow-up observations at optical, X-ray, and radio wavelengths. I will describe how this approach has enabled us to answer decades-old questions in the field of gamma-ray bursts, learn what happens during the final days of a star's life, and discover unexpected types of cosmic explosions that are prime targets for millimeter-band observatories such as ALMA and eventually CMB-S4. I will summarize the implications for the next generation of time-domain surveys spanning the electromagnetic spectrum: how to most effectively use those observations to connect the final stages of stellar evolution and the formation (and afterlives) of compact objects to the observed characteristics of transients and remnants, and ultimately rewrite the story of massive-star evolution.