Engines, Lighthouses and Laboratories: Massive Stars Across the Cosmos
Emily Levesque

Massive stars are vital building blocks in our universe, with applications as astrophysical tools that span a broad range of subfields. The radiative signatures of star-forming galaxies are powered by their massive stellar populations. Transient phenomena act as observational beacons, ranging from local non-terminal events signaling the death throes of extreme massive stars to long-duration gamma-ray bursts that can serve as powerful probes of the high-redshift universe. Finally, resolved massive star populations offer a treasure trove of nearby targets, allowing us to closely examine their physical parameters, evolution, and contribution to chemical enrichment. I will discuss some of my current research programs focused on developing a comprehensive picture of massive stars across the cosmos: observational surveys and models of star-forming galaxies, progenitor and host environment studies of transient phenomena, and extragalactic stellar observations, including the recent discovery of the first Thorne-Zytkow object candidate. Combined, this work will make substantial progress in our understanding of massive stars over the coming decade. This in turn equips us with the tools we need to take full advantage of the frontiers opened up by new observational facilities such as LSST, the ELTs, and JWST, allowing us to immediately begin probing the new corners of the universe that they reveal.