Kishalay De (Columbia University): "More than two decades of the variable infrared sky revealed with NEOWISE, SPHEREx and Roman"

Time-domain surveys are transforming our view of the universe -- providing fundamental insights into the dominance of dynamic, short-lived phenomena in shaping the cosmos. Yet much of its transient activity remains hidden by clouds of gas and dust that limit X-ray, UV and optical surveys. In this talk, I will discuss the transformative discoveries in the variable infrared sky enabled by mining of archival data from the NEOWISE survey. By reprocessing 15 years of unWISE images with modern time-domain alert infrastructure as part of the WISE Transients Project (WTP), we have created an all-sky catalog of ~ 20M variable and eruptive infrared sources. The resulting discoveries have been rich and diverse, ranging from glimpses of the death of planets and mergers of stars to the birth and growth of black holes. I will conclude with the exciting coming decade of infrared surveys—highlighting the capabilities of the Roman Space Telescope in the dusty Galactic plane and high-redshift universe and the remarkable spectroscopic capabilities of the SPHEREx survey for variable infrared sources.