Characterizing and mitigating pulsar timing errors caused by intrinsic pulse shape variability

Jitter noise — the phenomenon of time-of-arrival errors caused by intrinsic variability in the shape of pulsar pulses — is an important factor limiting the precision of current and future pulsar timing efforts. We describe a method for characterizing it in detail, and mitigating its effects on pulsar timing, using the covariance matrix of the observed pulse profiles. Like the average pulse shape, the covariance matrix is expected to be stable over long periods of time. Because it encodes common modes of variation of the pulse shape, it can be used to identify the shape change affecting a particular profile, and thereby to better estimate the corresponding time of arrival.