How to Train Your Pulsar: Timing J1713+0747 with Pulse Profile Components

The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) achieves a timing precision below 100 ns for the millisecond pulsar J1713+0747, making it one of the most precisely timed pulsars in the array. However, in April 2021, J1713+0747 underwent a sudden and unusual pulse shape change that disrupted its timing stability. As a key contributor to pulsar timing array (PTA) sensitivity, variations in the pulse profile of J1713+0747 significantly affect the array's sensitivity to nanohertz gravitational waves. We apply Gaussian component fitting to decompose the pulse profile and track the evolution of individual components through the event. This component-level method maintains stable timing across the shape change, allowing data from the event to be included in PTA analyses, thus improving astrophysical constraints on the nanohertz gravitational-wave background.