Pulsar Discoveries from the TRAPUM UHF Survey of Fermi-LAT Sources

TL;DR

This study used MeerKAT UHF observations to discover 15 new pulsars from Fermi-LAT sources, confirming gamma-ray associations and demonstrating UHF's superior sensitivity over L band for faint pulsar detection.

Contribution

First UHF-band survey of Fermi-LAT sources with MeerKAT, discovering new pulsars and demonstrating UHF's advantages over L band in sensitivity and detection rate.

Findings

Discovered nine new millisecond pulsars and six slow pulsars.

Confirmed gamma-ray associations for seven MSPs through joint timing.

UHF observations outperform L band in detecting faint gamma-ray pulsars.

Abstract

The Fermi Large Area Telescope (LAT) provides advantages for radio pulsar searches by enabling efficient target selection. We can confidently point radio telescopes to the positions of Fermi unidentified gamma-ray sources that have a high probability of hosting a pulsar. As part of Transients and Pulsars with MeerKAT (TRAPUM), we conducted a survey of Fermi-LAT sources using the Ultra High Frequency (UHF; 544-1088 MHz) receiver of the MeerKAT radio telescope. We observed 79 sources that were identified as pulsar-like candidates using a random forest technique from the Fermi-LAT Fourth Source Catalogue. We observed each target for 10 minutes at two separate epochs. As a result, we discovered nine new millisecond pulsars (MSPs) and six slow pulsars. Based on the radio discoveries, we also searched for gamma-ray pulsations, confirming that seven of the newly discovered MSPs are associated with Fermi-LAT sources, and performed joint radio and gamma-ray pulsar timing. Companion mass estimates and evidence of radio eclipses indicate that among the nine MSPs there are three black widows and three redbacks. Lastly, we compared the discovered pulsars in the MeerKAT UHF survey against the previous Fermi sources TRAPUM survey at L band, concluding the superiority of UHF observations in sensitivity to fainter pulsars and in detection rate than L band for finding new gamma-ray MSPs.