Astrophysics Milestones For Pulsar Timing Array Gravitational Wave Detection

The North American Nanohertz Observatory for Gravitational waves (NANOGrav) recently reported what might be the first hints of a nanohertz stochastic gravitational wave background (GWB). Assuming that the signal found in the NANOGrav analysis is indeed the GWB, I will describe how the signal should evolve in significance over the next several years, as well as science that will be unlocked by the eventual detection of this signal. I will also describe how combining the data from individual pulsar timing arrays (PTAs) around the world into the International Pulsar Timing Array (IPTA) will allow us to extract scientific results out of the GWB significantly quicker than possible with individual PTAs.