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Investigating star-formation and supernovae in Messier-82
Dissertation (MSc (Physics))--University of Pretoria, 2025.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2025
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| _version_ | 1867613503949373440 |
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| access_status_str | Open Access |
| author2 | Radcliffe, Jack F. |
| author_browse | Radcliffe, Jack F. |
| author_facet | Radcliffe, Jack F. |
| collection | Thesis |
| dc_rights_str_mv | © 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc (Physics))--University of Pretoria, 2025. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/102378 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:11.641Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/102378 Investigating star-formation and supernovae in Messier-82 Radcliffe, Jack F. sibongumusa.ws@gmail.com Williams-Baldwin, David Shungube, Sibongumusa Wiseman UCTD Sustainable Development Goals (SDGs) Supernova remnants Spectral index analysis Starburst galaxies e-MERLIN observations Compact radio sources Dissertation (MSc (Physics))--University of Pretoria, 2025. Context: Messier 82 (M82) is a well-studied nearby starburst galaxy, home to numerous compact radio sources, including supernova remnants (SNRs) and HII regions. The high star formation rate (SFR) in M82 leads to frequent supernovae (SNe), making it an ideal laboratory for studying compact radio sources in a dense starburst environment. Aims: This thesis aims to catalog and analyze compact radio sources in the central region of M82 using new 1.5 GHz e-MERLIN observations. The study provides updated classifications for previously known sources and identifies new objects, contributing to our understanding of supernova (SN) activity and star formation (SF) in M82. Methods: The dataset was obtained from e-MERLIN L-band observations in 2016, processed using CASA for calibration and imaging. Compact sources were detected using PyBDSF. Sources were selected based on a signal-to-noise ratio (S/N) threshold of 6, ensuring reliable detections. Spectral indices were derived from multi-frequency subband imaging and combined with existing C-band (5 GHz) flux measurements to refine classifications. Morphological analysis was also performed to distinguish between SNRs and HII regions. Results: A total of 36 compact sources were identified, including 31 previously known objects and four newly detected sources. A key finding of this study is the reclassification of source 38.76+53.5, previously thought to be an HII region, as an SNR based on its steep spectral index (-1.054). This demonstrates the importance of multi-frequency spectral analysis in accurately identifying radio sources in starburst environments. Additionally, comparisons with previous studies from 2008 C-band observation confirmed the persistence of known sources while revealing discrepancies in classification. The spectral properties of 41.95+57.5 were further analyzed, contributing to the ongoing debate about its nature, while observations of SN 2008iz suggest it has now transitioned into a SNR. These findings refine existing classifications and contribute to a deeper understanding of the radio source population in M82. While this study does not establish a complete catalogue, it provides an updated dataset that enhances our knowledge of the physical processes shaping radio emission in starburst galaxies. Future multi-wavelength and long-term monitoring studies will be essential for further constraining the nature and evolution of these sources. National Astrophysics and Space Science Programme (NASSP) Physics MSc (Physics) Unrestricted Faculty of Natural and Agricultural Sciences None 2025-05-13T14:16:39Z 2025-05-13T14:16:39Z 2025-09 2025-04 Dissertation * S2025 http://hdl.handle.net/2263/102378 DOI: https://doi.org/10.25403/UPresearchdata.28890959.v2 https://doi.org/10.25403/10.25403/UPresearchdata.28890959 en © 2024 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Sustainable Development Goals (SDGs) Supernova remnants Spectral index analysis Starburst galaxies e-MERLIN observations Compact radio sources Investigating star-formation and supernovae in Messier-82 |
| title | Investigating star-formation and supernovae in Messier-82 |
| title_full | Investigating star-formation and supernovae in Messier-82 |
| title_fullStr | Investigating star-formation and supernovae in Messier-82 |
| title_full_unstemmed | Investigating star-formation and supernovae in Messier-82 |
| title_short | Investigating star-formation and supernovae in Messier-82 |
| title_sort | investigating star formation and supernovae in messier 82 |
| topic | UCTD Sustainable Development Goals (SDGs) Supernova remnants Spectral index analysis Starburst galaxies e-MERLIN observations Compact radio sources |
| url | http://hdl.handle.net/2263/102378 https://doi.org/10.25403/10.25403/UPresearchdata.28890959 |