Speaker: Prajwal Padmanabh (chair: Yuxin Lin)
Title: Long term profile stability of J1022+1001
Understanding pulsar profile instability is key to placing accurate limits on the detectability of gravitational waves with pulsar timing arrays. The profile stability of PSR J1022+1001 is investigated. Data from the Effelsberg Pulsar Observation System (EPOS) which operated in the 1990s and 2000s is combined along with the new Asterix backend to achieve decades-long baselines. PSR J1022+1001 is particularly interesting as separate analyses lead to disagreements in literature over the timing precision achievable due to intrinsic profile variation (Kramer et al. 1998, Hotan et al. 2004). In an attempt to resolve this apparent contradiction, Parkes data is included and both analyses are reproduced.
In addition, I will present an adaption of previous techniques to measure relative amplitude and position of peaks in multi-component pulsars using a polynomial fit and compare this against previously published techniques. Polarisation is known to affect pulse shape, thus robust calibration is critical to high precision pulsar timing. Miscalibration has been cited as a potential source of discrepancy in previous analyses of J1022+1001 (Hotan et al. 2004). The results from the profile shape analysis are compared with the effects of polarisation miscalibration.