Hypervariable galactic nuclei

Extreme variability in the intensity of the optical light of galaxies, by factors of two or more, is of great interest to astronomers. It can flag the presence of rare types of supernovae, for example, or spot sudden accretion activity around quiescent black holes or around the supermassive black hole at the galaxy's nucleus. In recent years systematic searches for such variability have been made using instruments that can survey wide swaths of the sky. One, the Panoramic Survey Telescope &