Searching for pulsars in Globular Clusters with the Fast Fold Algorithm and a new pulsar discovered in M13

TL;DR

This study used the Fast Folding Algorithm on FAST telescope data to discover a new pulsar in M13 and re-detected known pulsars, revealing diverse evolutionary paths in globular clusters.

Contribution

The paper demonstrates the effectiveness of FFA in detecting long-period pulsars and reports the discovery and detailed timing of a new binary millisecond pulsar in M13.

Findings

Successfully re-detected most known pulsars in 16 globular clusters.

Discovered a new binary millisecond pulsar, M13I, with unique orbital properties.

Identified challenges in detecting pulsars with high accelerations.

Abstract

We employed the Fast Folding Algorithm (FFA) on L-Band Globular Cluster (GC) observations taken with Five-hundred-meter Aperture Spherical radio Telescope (FAST) to search for new pulsars, especially those with a long rotational period. We conducted a search across 16 GCs that collectively host 93 known pulsars, as well as 14 GCs that do not contain any known pulsars. The majority of these known pulsars were successfully re-detected in our survey. The few non-detections could be attributed to the high accelerations of these pulsars. Additionally, we have discovered a new binary millisecond pulsar, namely M13I (or PSR J1641+3627I) in GC M13 (or NGC 6205), and obtained its phase-coherent timing solution using observations spanning 6 years. M13I has a spin period of 6.37 ms, and an orbital period of 18.23 days. The eccentricity of the binary orbit is 0.064, with a companion mass range of approximately 0.45 to 1.37 M$_{\odot}$. The orbital properties of M13I are remarkably different from those of the other known pulsars in M13, indicating that this pulsar has undergone a different evolutionary path compared to the rest.