Session P01: Closing Plenary Session

NANOGrav: Gravitational Waves (and other cool science) from Pulsar Timing

In 2023, NANOGrav and the rest of the pulsar timing array community announced strong evidence for the presence of a stochastic background of nanoHertz frequency gravitational waves. This has been the primary goal of the community for the past two decades, and it took thousands of hours of observations of many dozens of millisecond pulsars, and a highly sophisticated analysis effort to accomplish. In this talk I'll explain how these, and many other astonishing measurements, are all possible via the miracle technique of pulsar timing.   

Strong-field tests of gravity with gravitational waves

Recent observations of black holes through gravitational waves allow us to probe the strong and dynamical field regime of gravity. After briefly reviewing General Relativity, black holes, and gravitational waves, I will describe a parameterized test of gravity with gravitational waves to probe different fundamental aspects of General Relativity in a theory-agnostic approach. I will then explain how this parameterized test can be mapped to specific theories, taking as an example a gravitational theory beyond General Relativity that is motivated by string theory.