TRAPUM upper limits on pulsed radio emission for SMC X-ray pulsar J0058-7218

TL;DR

The study used MeerKAT to search for pulsed radio emission from the SMC X-ray pulsar J0058-7218, setting a deep upper limit and finding no significant radio signals, suggesting its emission may be beamed away or intrinsically weak.

Contribution

First deep radio upper limit on SMC X-ray pulsar J0058-7218 using MeerKAT, improving sensitivity over previous searches and exploring its emission properties.

Findings

No pulsed radio emission detected above 7.0 μJy at 1284 MHz.

No bright single pulses found above 93 mJy ms fluence.

Results imply the pulsar's radio emission is either beamed away or intrinsically faint.

Abstract

The TRAPUM collaboration has used the MeerKAT telescope to conduct a search for pulsed radio emission from the young Small Magellanic Cloud pulsar J0058-7218 located in the supernova remnant IKT 16, following its discovery in X-rays with XMM-Newton. We report no significant detection of dispersed, pulsed radio emission from this source in three 2-hour L-band observations using the core dishes of MeerKAT, setting an upper limit of 7.0 {\mu}Jy on its mean flux density at 1284 MHz. This is nearly 7 times deeper than previous radio searches for this pulsar in Parkes L-band observations. This suggests that the radio emission of PSR J0058-7218 is not beamed towards Earth or that PSR J0058-7218 is similar to a handful of Pulsar Wind Nebulae systems that have a very low radio efficiency, such as PSR B0540-6919, the Large Magellanic Cloud Crab pulsar analogue. We have also searched for bright, dispersed, single radio pulses and found no candidates above a fluence of 93 mJy ms at 1284 MHz.