The NANOGrav Nine-Year Data Set: Noise Budget for Pulsar Arrival Times on Intraday Timescales

Understand

The use of pulsars as astrophysical clocks for gravitational wave experiments demands the highest possible timing precision.

• Pulse times of arrival (TOAs) are limited by stochastic processes that occur in the pulsar itself, along the line of sight through the interstellar medium, and in the measurement process.
• On timescales of seconds to hours, the TOA variance exceeds that from template-fitting errors due to additive noise.
• We assess contributions to the total variance from two additional effects: amplitude and phase jitter intrinsic to single pulses and changes in the interstellar impulse response from scattering.