A Beginner's Guide to Gravitational Wave Detection with Pulsar Timing Arrays*

Pulsar timing arrays are sensitive to low-frequency gravitational waves with periods of months to decades, such as those emitted by supermassive binary black holes at subparsec separations. They do so by precisely timing a collection of millisecond pulsars, whose extremely stable rotation makes them ideal for measuring perturbations in spacetime. Gravitational waves induce correlations in the pulse arrival times that follows a characteristic pattern known as the Hellings-Downs curve. Recently, pulsar timing array experiments around the world published the first evidence of nanohertz gravitational waves. In this talk, I will discuss how pulsar timing arrays detect gravitational waves, how we construct pulsar timing arrays, and some of the challenges in extracting gravitational wave signals from pulsar observations.