The NANOGrav 15-year Data Set: Pulsar Timing, the Gravitational Wave Background, and Beyond

After more than 15 years of data collection, pulsar timing arrays, including the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), have at last uncovered evidence of a stochastic background of gravitational waves. In this talk, I'll give an overview of pulsar timing array science and NANOGrav's 15-year data set, before detailing the methods and results of our searches for the gravitational wave background. I'll then expand to describe implications for supermassive black hole binary science, additional searches for binary signals, and finally, describe the thrilling opportunities for multi-messenger science in the coming years.