Timing and noise analysis of five millisecond pulsars observed with MeerKAT

TL;DR

This study analyzes timing and noise in five millisecond pulsars observed with MeerKAT, detecting Shapiro delays to measure neutron star and companion masses, with one notably low-mass pulsar, contributing to dense matter physics and gravitational wave research.

Contribution

First detailed timing and noise analysis of five MSPs with MeerKAT, including the detection of Shapiro delays and precise mass measurements, expanding pulsar mass data and gravitational wave studies.

Findings

Detected Shapiro delay in three pulsars, with a significant measurement for PSR J1543-5149.

Measured neutron star mass of approximately 1.35 solar masses for PSR J1543-5149.

Provided proper motion and parallax constraints for most pulsars.

Abstract

Millisecond pulsars (MSPs) in binary systems are precise laboratories for tests of gravity and the physics of dense matter. Their orbits can show relativistic effects that provide a measurement of the neutron star mass and the pulsars are included in timing array experiments that search for gravitational waves. Neutron star mass measurements are key to eventually solving the neutron star equation of state and these can be obtained by a measure of the Shapiro delay if the orbit is viewed near edge-on. Here we report on the timing and noise analysis of five MSPs observed with the MeerKAT radio telescope: PSRs J0900$-$3144, J0921$-$5202, J1216$-$6410, J1327$-$0755 and J1543$-$5149. We searched for the Shapiro delay in all of the pulsars and obtain weak detections for PSRs J0900$-$3144, J1216$-$6410, and J1327$-$0755. We report a higher significance detection of the Shapiro delay for PSR J1543$-$5149, giving a precise pulsar mass of $M_{\rm p} = 1.349^{+0.043}_{-0.061}\,$M$_\odot$ and companion white-dwarf mass $M_{\rm c} = 0.223^{+0.005}_{-0.007}\,$M$_\odot$. This is an atypically low mass measurement for a recycled MSP. In addition to these Shapiro delays, we also obtain timing model parameters including proper motions and parallax constraints for most of the pulsars.