Limits on the Stochastic Gravitational Wave Background from the North American Nanohertz Observatory for Gravitational Waves

Understand

We present an analysis of high-precision pulsar timing data taken as part of the North American Nanohertz Observatory for Gravitational waves (NANOGrav) project.

• We have observed 17 pulsars for a span of roughly five years using the Green Bank and Arecibo radio telescopes.
• We analyze these data using standard pulsar timing models, with the addition of time-variable dispersion measure and frequency-variable pulse shape terms.
• Sub-microsecond timing residuals are obtained in nearly all cases, and the best root-mean-square timing residuals in this set are ~30-50 ns.