Limits on the Mass, Velocity and Orbit of PSR J1933$-$6211

TL;DR

This study uses high-precision polarimetric timing of PSR J1933-6211 to constrain the system's orbital parameters and companion mass, suggesting a likely CO white dwarf companion and a pulsar mass exceeding 1.0 solar masses.

Contribution

The paper applies matrix template matching with full polarimetric data to improve timing precision and constrains the companion's nature and mass in the PSR J1933-6211 system.

Findings

Achieved 1.23 μs timing residuals with polarimetric analysis.

Placed a 2-σ upper limit of 0.44 M☉ on the companion mass.

Concluded the companion is likely a CO white dwarf, implying a pulsar mass > 1.0 M☉.

Abstract

We present a high-precision timing analysis of PSR J1933$-$6211, a millisecond pulsar (MSP) with a 3.5-ms spin period and a white dwarf (WD) companion, using data from the Parkes radio telescope. Since we have accurately measured the polarization properties of this pulsar we have applied the matrix template matching approach in which the times of arrival are measured using full polarimetric information. We achieved a weighted root-mean-square timing residuals (rms) of the timing residuals of 1.23 $\rm \mu s$, 15.5$\%$ improvement compared to the total intensity timing analysis. After studying the scintillation properties of this pulsar we put constraints on the inclination angle of the system. Based on these measurements and on $\chi^2$ mapping we put a 2-$\sigma$ upper limit on the companion mass (0.44 M$_\odot$). Since this mass limit cannot reveal the nature of the companion we further investigate the possibility of the companion to be a He WD. Applying the orbital period-mass relation for such WDs, we conclude that the mass of a He WD companion would be about 0.26$\pm$0.01 M$_\odot$ which, combined with the measured mass function and orbital inclination limits, would lead to a light pulsar mass $\leqslant$ 1.0 M$_\odot$. This result seems unlikely based on current neutron star formation models and we therefore conclude that PSR J1933$-$6211 most likely has a CO WD companion, which allows for a solution with a more massive pulsar.