Hunting for Hidden Explosions: Exploring the Transient Infrared Sky with the Spitzer Space Telescope

The study of time-variable astronomical phenomena is undergoing an explosive renaissance ushered in by recent advancements in capabilities to monitor the sky from radio to gamma rays. The infrared region of the electromagnetic spectrum provides a unique window to uncover a vast array of stellar eruptions and explosions that are otherwise obscured; however, the dynamic infrared sky has remained largely unexplored. To uncover these hidden cosmic explosions, I undertook a systematic search in the infrared with the Spitzer Space Telescope called SPIRITS — the SPitzer InfraRed Intensive Transients Survey. Targeting a specially chosen sample of nearby galaxies, the search revealed a bounty of exceptionally red events, and may have discovered entirely new and diverse populations, including deeply embedded supernovae, catastrophic stellar mergers, and giant eruptions of massive, violently unstable stars. Providing a first census of stellar infrared transients, SPIRITS has paved the way for new and upcoming surveys to further expand our exploration of the dynamic infrared sky.</p