A glitch in the millisecond pulsar J0900$-$3144

TL;DR

This paper reports the detection of a small glitch in the millisecond pulsar J0900$-$3144, adding valuable data to pulsar timing arrays and highlighting potential biases in gravitational wave detection efforts.

Contribution

First detection of a glitch in PSR J0900$-$3144, expanding knowledge of MSP glitch phenomena and implications for pulsar timing array analyses.

Findings

Detected a glitch with fractional frequency step of 1.15e-12.

Estimated MSP glitch rate is approximately 2.5e-3 glitches per pulsar per year.

Small glitches can be missed in short datasets and bias noise models.

Abstract

We report the detection of a glitch in the millisecond pulsar (MSP) PSR J0900$-$3144, which is included in the European, MeerKAT and Parkes pulsar timing array experiments. The dataset combines observations from the MeerKAT, Nan\c{c}ay, Lovell, and Murriyang telescopes, spanning a total baseline of approximately 14 years. The glitch occurred on MJD~59942(17), with a measured fractional spin frequency step of $\Delta \nu_g / \nu=1.15(13) \times 10^{-12}$. This event represents the third glitch detected in a MSP, following those in PSRs B1821$-$24A and J0613$-$0200. Although smaller in amplitude than the previous two, the glitch in PSR J0900$-$3144 is of a comparable order of magnitude. The updated MSP glitch rate is $2.5(1)\times 10^{-3}$ glitches per pulsar per year, which suggests it is likely current PTAs will detect another MSP glitch within five years. Using simulations, we demonstrate that such small glitches can go undetected, especially in short datasets such as those from new PTAs, and can bias the inferred achromatic noise model parameters, potentially leading to the down-weighting of the pulsar in gravitational wave background searches.