New ASKAP Radio Supernova Remnants and Candidates in the Large Magellanic Cloud

TL;DR

This paper reports the discovery of 14 new radio supernova remnant candidates in the Large Magellanic Cloud using ASKAP, expanding the known population and providing insights into their environments and multi-frequency properties.

Contribution

It introduces a new ASKAP-based sample of 14 LMC SNR candidates, including detailed multi-frequency analysis and confirmation of some candidates' SNR nature, enhancing the understanding of SNR diversity.

Findings

14 new SNR candidates identified with ASKAP

Confirmation of the SNR nature of one candidate and validation of another

Detection of SNRs in low-density environments and those formed by stellar winds

Abstract

We present a new Australian Square Kilometre Array Pathfinder (ASKAP) sample of 14 radio Supernova Remnant (SNR) candidates in the Large Magellanic Cloud (LMC). This new sample is a significant increase to the known number of older, larger and low surface brightness LMC SNRs. We employ a multi-frequency search for each object and found possible traces of optical and occasionally X-ray emission in several of these 14 SNR candidates. One of these 14 SNR candidates (MCSNR J0522-6543) has multi-frequency properties that strongly indicate a bona fide SNR. We also investigate a sample of 20 previously suggested LMC SNR candidates and confirm the SNR nature of MCSNR J0506-6815. We detect lower surface brightness SNR candidates which were likely formed by a combination of shock waves and strong stellar winds from massive progenitors (and possibly surrounding OB stars). Some of our new SNR candidates are also found in a lower density environments in which SNe type Ia explode inside a previously excavated interstellar medium (ISM).