Connecting the Young Pulsars in Milky Way Globular Clusters with White Dwarf Mergers and the M81 Fast Radio Burst

TL;DR

This paper proposes that young pulsars in Milky Way globular clusters originate from white dwarf mergers, explaining their properties and linking them to fast radio bursts observed in a nearby galaxy.

Contribution

It introduces a novel formation channel for young pulsars via white dwarf mergers in old clusters, connecting pulsar properties with fast radio bursts.

Findings

White dwarf mergers can produce neutron stars with observed pulsar properties.

Simulations support the merger origin based on cluster dynamics and pulsar characteristics.

Young pulsars may be linked to fast radio bursts from similar neutron stars.

Abstract

The detections of four apparently young radio pulsars in the Milky Way globular clusters are difficult to reconcile with standard neutron star formation scenarios associated with massive star evolution. Here we discuss formation of these young pulsars through white dwarf mergers in dynamically-old clusters that have undergone core collapse. Based on observed properties of magnetic white dwarfs, we argue neutron stars formed via white dwarf merger are born with spin periods of roughly $10-100\,$ms and magnetic fields of roughly $10^{11}-10^{13}\,$G. As these neutron stars spin down via magnetic dipole radiation, they naturally reproduce the four observed young pulsars in the Milky Way clusters. Rates inferred from $N$-body cluster simulations as well as the binarity, host cluster properties, and cluster offsets observed for these young pulsars hint further at a white dwarf merger origin. These young pulsars may be descendants of neutron stars capable of powering fast radio bursts analogous to the bursts observed recently in a globular cluster in M81.