The discovery of three pulsars in the globular cluster M15 with the FAST

TL;DR

This paper reports the discovery of three new pulsars in the globular cluster M15 using the FAST telescope, including the longest-period pulsar known in this cluster, and updates timing solutions for several previously known pulsars.

Contribution

First discovery of three pulsars in M15 with FAST, including the longest-period pulsar, and updated timing solutions for multiple pulsars in the cluster.

Findings

Discovered three pulsars: one millisecond and two long-period pulsars.

Identified the longest spin period pulsar in M15.

Detected the flux density decrease of M15C and first detection of M15I since discovery.

Abstract

We present the discovery of three pulsars in the Globular Cluster (GC) M15 (NGC 7078) by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). PSR J2129+1210J (M15J) is a millisecond pulsar with a spin period of 11.84 ms and a dispersion measure of 66.68 pc cm-3. Both PSR J2129+1210K and L (M15K and L) are long-period pulsars with spin periods of 1928 ms and 3961 ms, respectively. M15L is the GC pulsar with the longest spin period known. The timing solutions of M15A to M15H are updated. As predicted by Ridolfi et al.(2018), the flux density of M15C keeps decreasing and the latest detection in our dataset was on December 20th, 2022. We have also detected M15I's signal for the first time since its discovery. Current timing suggests that it is an isolated pulsar.