Wideband timing of the Parkes Pulsar Timing Array UWL data

TL;DR

This paper demonstrates the application of wideband timing techniques to a three-year dataset of 35 millisecond pulsars observed with the Parkes UWL receiver, improving timing precision and modeling pulse evolution.

Contribution

First application of wideband timing to a uniform large-bandwidth pulsar data set, introducing two-dimensional templates and simultaneous ToA and DM measurements.

Findings

Achieved median ToA uncertainty below 1 microsecond for 94% of pulsars.

Developed pulse profile evolution models for wideband data.

Provided new timing solutions and initial noise analysis.

Abstract

In 2018 an ultra-wide-bandwidth low-frequency (UWL) receiver was installed on the 64-m Parkes Radio Telescope enabling observations with an instantaneous frequency coverage from 704 to 4032 MHz. Here, we present the analysis of a three-year data set of 35 millisecond pulsars observed with the UWL by the Parkes Pulsar Timing Array (PPTA), using wideband timing methods. The two key differences compared to typical narrow-band methods are, firstly, generation of two-dimensional templates accounting for pulse shape evolution with frequency and, secondly, simultaneous measurements of the pulse time-of-arrival (ToA) and dispersion measure (DM). This is the first time that wideband timing has been applied to a uniform data set collected with a single large-fractional bandwidth receiver, for which such techniques were originally developed. As a result of our study, we present a set of profile evolution models and new timing solutions including initial noise analysis. Precision of our ToA and DM measurements is in the range of 0.005 $-$ 2.08 $\mu$s and (0.043$-$14.24)$\times10^{-4}$ cm$^{-3}$ pc, respectively, with 94% of the pulsars achieving a median ToA uncertainty of less than 1 $\mu$s.