Detection of 49 Weak Dispersed Radio Pulses in a Parkes Observation of the X-ray Pulsar PSR J0537$-$6910

TL;DR

A detailed search for dispersed radio pulses from the X-ray pulsar PSR J0537$-$6910 in the Large Magellanic Cloud identified 49 weak pulses, with three potential repeats, suggesting possible pulsar activity but no definitive detection.

Contribution

This study presents the first extensive archival search for radio pulses from PSR J0537$-$6910, revealing weak pulses and potential repeats, expanding understanding of pulsar radio emission in the LMC.

Findings

Detected 49 weak dispersed radio pulses with S/N > 7.

Identified three repeat pulses at a specific DM, unlikely by chance.

No conclusive evidence that pulses originate from PSR J0537$-$6910.

Abstract

I conducted a new search for dispersed radio pulses from the X-ray pulsar PSR J0537$-$6910 in the Large Magellanic Cloud in a long (11.6 hr) archival 1.4 GHz Parkes search observation. I searched dispersion measures (DMs) between 0 and 10000 pc cm$^{-3}$ and detected 49 pulses with a signal-to-noise ratio (S/N) greater than 7 at a wide range of DMs using the HEIMDALL and FETCH pulse detection and classification packages. All of the pulses were weak, with none having a S/N above 8.5. There was a significant excess of pulses observed in the DM range of the known pulsar population in the LMC, suggesting that these pulses may originate from LMC pulsars. Three repeat pulses, each having widths $\lesssim 1$ ms, were detected in a single DM trial of 103.412 pc cm$^{-3}$, which is in the LMC DM range. This is unlikely to occur by chance in a single DM trial in this search at the (marginally significant) 4.3$\sigma$ level. It remains unclear whether any of the detected pulses in the sample are from PSR J0537$-$6910 itself.