A multi-wavelength investigation of supernova remnants in the large magellanic cloud, with a focus on embedded pulsar wind nebulae

Abstract

Supernova remnants (SNRs) are the expanding structures that result from the explosive death of stars. These remnants play a vital role in shaping the interstellar medium (ISM) by distributing heavy elements and injecting large amounts of energy into their surroundings. As key agents in both the dynamical and chemical evolution of galaxies, SNRs operate as essential probes for understanding stellar feedback mechanisms, nucleosynthesis, and the life cycle of baryonic matter in the universe.

This thesis presents an in-depth, multi-wavelength analysis of a selected sample of s in the Large Magellanic Cloud (LMC), with a particular focus on identifying and characterising remnants that host Pulsar Wind Nebula (PWN). We analysed new and archival radio- continuum observations from Australia Telescope Compact Array (ATCA), Australian Square Kilometre Array Pathfinder (ASKAP), and MeerKAT, complemented by multi-wavelength data including Chandra X-ray and Magellanic Cloud Emission Line Survey (MCELS) optical images. The well-known N 49 is re-examined in light of new polarimetric and continuum data, revealing a high-velocity (∼2000 km s−1) bullet-like feature located beyond the southwestern boundary of the shell. This feature appears to be morphologically and physically connected to the SNR, as supported by X-ray and polarisation analysis. A detailed spectral index map of N 49 yields 𝛼 = −0.55 ± 0.03, consistent with middle-aged remnants, and Faraday rotation measurements indicate complex magnetic field structures.

The broader population analysis supports the view that many of these remnants result from core–collaps supernova (CCSN) in clustered star-forming environments, although some may originate from Type Ia events in evacuated regions. This multi-wavelength study enhances our understanding of the diversity of LMC SNRs, the conditions under which form, and the role of the local environment in shaping their evolution. The spatial correlation between several remnants and young stellar populations suggests that massive progenitors are common in this region. In contrast, the presence of a few s in more diffuse or isolated environments is consistent with Type Ia origins. By combining radio, X-ray, and optical data, this work offers new insights into how the progenitor type, explosion energy, and ambient medium influence the observed morphology and emission properties of each remnant.

Date of Thesis submission	2025
Original language	English
Awarding Institution	Western Sydney University
Sponsors	Australian Government Research Training Program Scholarship
Supervisor	Miroslav Filipovic (Supervisor) & Nick Tothill (Supervisor)