Collaborative Research: Building the Next-Generation NANOGrav Pulsar Timing Array with the DSA-2000

Enormous black holes a billion times more massive than the Sun orbit and merge with each other in the hearts of distant galaxies. These mergers produce gravitational waves, ripples in the fabric of space-time itself, with periods of years. Recently, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration confirmed the existence of these ripples. The collaboration has been observing cosmic clocks, called "millisecond pulsars", for 15 years. Gravitational waves stretch and squeeze space-time, making these clocks appear to speed up and slow down. The observation that these clocks vary in concert, not independently, reveals the existence of these gravitational waves. Making these observations requires radio telescopes of enormous sensitivity. The NANOGrav collaboration has been partnering with the DSA-2000 project to build a telescope that can continue these observations. Graduate and undergraduate students will receivehands-on training on the development of hardware and algorithms. The results will be presented widely to the scientific community as well as the broader public. This award contributes to the goals of NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" meta-program by including the development of metrics to evaluate millisecond pulsars for their timing suitability, and the selection of an expanded sample for timing observations. It will support the development and deployment of pulsar timing instrumentation and pipelines, and its commissioning on prototype hardware and the DSA-2000 telescope as construction proceeds. As a result, the infrastructure will be in place to accurately characterize the low-frequency gravitational wave background, and thus to characterize the astrophysics of supermassive black holes, as well as to potentially identify individual black hole binary systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.