Zoom Recording Passcode: 5!eb9T.F

Pulsar timing array experiments aim to detect nHz-frequency gravitational waves using high-precision timing of millisecond pulsars in the Milky Way. Multiple collaborations have recently reported evidence for a stochastic gravitational wave background, expected to arise predominantly from a population of inspiraling supermassive black hole binaries, but there may also be contributions from exotic cosmological sources that formed around the time of the Big Bang. In this talk, I will present the latest analyses from the NANOGrav collaboration and discuss possible interpretations. I will also describe how timing data can be used to search for metric perturbations due to the presence of ultralight dark matter in the Galaxy.