TRAPUM search for pulsars in supernova remnants and pulsar wind nebulae -- I. Survey description and initial discoveries

TL;DR

The paper describes the initial results of the TRAPUM survey using MeerKAT to find pulsars in supernova remnants and related objects, leading to two new pulsar discoveries and insights into neutron star populations.

Contribution

It introduces a novel interferometric beamforming technique with MeerKAT for targeted pulsar searches in SNRs and PWN, resulting in initial discoveries and improved search sensitivity.

Findings

Discovered two new pulsars: PSR J1831-0941 and PSR J1818-1502.

Achieved a flux density upper limit of 30 μJy for pulsar detection.

Demonstrated the effectiveness of the beamforming technique in targeted searches.

Abstract

We present the description and initial results of the TRAPUM (TRAnsients And PUlsars with MeerKAT) search for pulsars associated with supernova remnants (SNRs), pulsar wind nebulae and unidentified TeV emission. The list of sources to be targeted includes a large number of well-known candidate pulsar locations but also new candidate SNRs identified using a range of criteria. Using the 64-dish MeerKAT radio telescope, we use an interferometric beamforming technique to tile the potential pulsar locations with coherent beams which we search for radio pulsations, above a signal-to-noise of 9, down to an average flux density upper limit of 30 $\mu$Jy. This limit is target-dependent due to the contribution of the sky and nebula to the system temperature. Coherent beams are arranged to overlap at their 50 per cent power radius, so the sensitivity to pulsars is not degraded by more than this amount, though realistically averages around 65 per cent if every location in the beam is considered. We report the discovery of two new pulsars; PSR J1831$-$0941 is an adolescent pulsar likely to be the plerionic engine of the candidate PWN G20.0+0.0, and PSR J1818$-$1502 appears to be an old and faint pulsar that we serendipitously discovered near the centre of a SNR already hosting a compact central object. The survey holds importance for better understanding of neutron star birth rates and the energetics of young pulsars.