Timing analysis for 20 millisecond pulsars in the Parkes Pulsar Timing Array

TL;DR

This paper presents enhanced timing models for 20 millisecond pulsars in the Parkes Pulsar Timing Array, improving parameter precision through advanced noise modeling, and reports new measurements of parallax, orbital parameters, and pulsar masses.

Contribution

Introduces a new noise modeling procedure and incorporates annual DM variations, leading to more accurate pulsar timing models and the first significant measurements of several key parameters.

Findings

First significant parallax measurements for five pulsars.

Improved pulsar mass measurements, e.g., PSRs J0437-4715 and J1909-3744.

Highly precise distance measurement for PSR J0437-4715 at 0.16% accuracy.

Abstract

We present timing models for 20 millisecond pulsars in the Parkes Pulsar Timing Array. The precision of the parameter measurements in these models has been improved over earlier results by using longer data sets and modelling the non-stationary noise. We describe a new noise modelling procedure and demonstrate its effectiveness using simulated data. Our methodology includes the addition of annual dispersion measure (DM) variations to the timing models of some pulsars. We present the first significant parallax measurements for PSRs J1024-0719, J1045-4509, J1600-3053, J1603-7202, and J1730-2304, as well as the first significant measurements of some post-Keplerian orbital parameters in six binary pulsars, caused by kinematic effects. Improved Shapiro delay measurements have resulted in much improved pulsar mass measurements, particularly for PSRs J0437-4715 and J1909-3744 with $M_p=1.44\pm0.07$ $M_\odot$ and $M_p=1.47\pm0.03$ $M_\odot$ respectively. The improved orbital period-derivative measurement for PSR J0437-4715 results in a derived distance measurement at the 0.16% level of precision, $D=156.79\pm0.25$ pc, one of the most fractionally precise distance measurements of any star to date.