Searching For Stochastic Gravitational Waves Below a Nanohertz

Understand

The stochastic gravitational-wave background is imprinted on the times of arrival of radio pulses from millisecond pulsars.

• Traditional pulsar timing analyses fit a timing model to each pulsar and search the residuals of the fit for a stationary time correlation.
• This method breaks down at gravitational-wave frequencies below the inverse observation time of the array; therefore, existing analyses restrict their searches to frequencies above 1 nHz.
• An effective method to overcome this challenge is to study the correlation of secular drifts of parameters in the pulsar timing model itself.