A comparison of millisecond pulsar populations between globular clusters and the Galactic field

TL;DR

This study compares millisecond pulsars in globular clusters and the Galactic field, revealing differences in rotation, magnetic fields, and X-ray properties, highlighting the impact of dynamical interactions on their evolution.

Contribution

It provides a systematic comparison of MSP properties in GCs and GF, showing how cluster dynamics influence pulsar evolution and emission characteristics.

Findings

GC MSPs rotate slower than GF MSPs

No correlation between orbital and rotation periods in GCs

GC MSPs have stronger surface magnetic fields

Abstract

We have performed a systematic study of the rotational, orbital and X-ray properties of millisecond pulsars (MSPs) in globular clusters (GCs) and compared their nature with those of the MSPs in the Galactic field (GF). We found that GC MSPs generally rotate slower than their counterparts in the GF. Different from the expectation of a simple recycling scenario, no evidence for the correlation between the orbital period and the rotation period can be found from the MSP binaries in GCs. There is also an indication that the surface magnetic field of GC MSPs are stronger than those in the GF. All these suggest dynamical interactions in GCs can alter the evolution of MSPs/their progenitors which can leave an imprint on their X-ray emission properties. While the MSPs in both GF and GCs have similar distributions of X-ray luminosity and hardness, our sample supports the notion that these two populations follow different relation between the X-ray luminosity and spin-down power. We discuss this in terms of both pulsar emission model and the observational bias.