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The automated detection and multiwavelength properties of LADUMA HI galaxies
In this study, we investigate the neutral atomic hydrogen (HI) and star formation history (SFH) properties of 104 low redshift (0 < zHI < 0.088) galaxies from the Looking At the Distant Universe with the MeerKAT Array (LADUMA) survey. LADUMA is a deep and narrow HI emission survey underway with the...
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| Format: | Thesis |
| Language: | English English |
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Department of Astronomy
2026
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| _version_ | 1867613320169652224 |
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| access_status_str | Open Access |
| author | Stockenstroom, Leyya |
| author2 | Delhaize, Jacinta |
| author_browse | Delhaize, Jacinta Stockenstroom, Leyya |
| author_facet | Delhaize, Jacinta Stockenstroom, Leyya |
| author_sort | Stockenstroom, Leyya |
| collection | Thesis |
| description | In this study, we investigate the neutral atomic hydrogen (HI) and star formation history (SFH) properties of 104 low redshift (0 < zHI < 0.088) galaxies from the Looking At the Distant Universe with the MeerKAT Array (LADUMA) survey. LADUMA is a deep and narrow HI emission survey underway with the MeerKAT telescope. We perform automated source finding over the low redshift Early Science LADUMA data cube using the SoFiA-2 algorithm. The source finding mask created in this work will be used to clean the first public data release of the LADUMA data cubes, which will be outlined in an upcoming paper. We present the confirmed SoFiA-2 detections of HI and compare the results to those produced by manual and semi-automated methods of source finding. We find generally good agreement between the methods, suggesting that SoFiA-2 will be an efficient and effective method on subsequent LADUMA data cubes. Additionally, we perform spectral energy distribution (SED) fitting to far-ultraviolet (FUV) to far-infrared (FIR) multiband photometry of our HI sample, thereby determining their stellar masses (M∗), star formation rates (SFRs), and star formation histories (SFHs). We explore the relationship between galaxies' HI and star formation history properties (HI-SFH). To do this, we examine the lookback time of peak star formation (τpeak) versus the HI mass to stellar mass fraction (MHI /M∗) and the peak star formation rate versus MHI /M∗. The latter is investigated here for the first time, to the best of our knowledge. Our findings reveal a strong anti-correlation between MHI /M∗ and SFRpeak of our HI sample, with τpeak decreasing as MHI /M∗ increases. This suggests that galaxies with lower MHI /M∗ have previously undergone more aggressive periods of star formation than galaxies with higher MHI /M∗. Additionally, galaxies with higher MHI /M∗ exhibit rising star formation rates at the time of observation and are likely to reach their peak star formation rate in future stages of their evolution. These findings serve as a low redshift pilot study, which can be applied to and compared with similar source finding and HI-SFH studies in upcoming higher redshift data from the LADUMA survey. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/42708 |
| institution | University of Cape Town (South Africa) |
| language | English eng |
| last_indexed | 2026-06-10T12:34:14.045Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Department of Astronomy |
| publisherStr | Department of Astronomy |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/42708 The automated detection and multiwavelength properties of LADUMA HI galaxies Stockenstroom, Leyya Delhaize, Jacinta Jarvis, Matt LADUMA MeerKAT Array In this study, we investigate the neutral atomic hydrogen (HI) and star formation history (SFH) properties of 104 low redshift (0 < zHI < 0.088) galaxies from the Looking At the Distant Universe with the MeerKAT Array (LADUMA) survey. LADUMA is a deep and narrow HI emission survey underway with the MeerKAT telescope. We perform automated source finding over the low redshift Early Science LADUMA data cube using the SoFiA-2 algorithm. The source finding mask created in this work will be used to clean the first public data release of the LADUMA data cubes, which will be outlined in an upcoming paper. We present the confirmed SoFiA-2 detections of HI and compare the results to those produced by manual and semi-automated methods of source finding. We find generally good agreement between the methods, suggesting that SoFiA-2 will be an efficient and effective method on subsequent LADUMA data cubes. Additionally, we perform spectral energy distribution (SED) fitting to far-ultraviolet (FUV) to far-infrared (FIR) multiband photometry of our HI sample, thereby determining their stellar masses (M∗), star formation rates (SFRs), and star formation histories (SFHs). We explore the relationship between galaxies' HI and star formation history properties (HI-SFH). To do this, we examine the lookback time of peak star formation (τpeak) versus the HI mass to stellar mass fraction (MHI /M∗) and the peak star formation rate versus MHI /M∗. The latter is investigated here for the first time, to the best of our knowledge. Our findings reveal a strong anti-correlation between MHI /M∗ and SFRpeak of our HI sample, with τpeak decreasing as MHI /M∗ increases. This suggests that galaxies with lower MHI /M∗ have previously undergone more aggressive periods of star formation than galaxies with higher MHI /M∗. Additionally, galaxies with higher MHI /M∗ exhibit rising star formation rates at the time of observation and are likely to reach their peak star formation rate in future stages of their evolution. These findings serve as a low redshift pilot study, which can be applied to and compared with similar source finding and HI-SFH studies in upcoming higher redshift data from the LADUMA survey. 2026-01-28T06:50:26Z 2026-01-28T06:50:26Z 2025 2026-01-28T06:44:13Z Thesis / Dissertation Masters MSc http://hdl.handle.net/11427/42708 en eng application/pdf Department of Astronomy Faculty of Science University of Cape Town |
| spellingShingle | LADUMA MeerKAT Array Stockenstroom, Leyya The automated detection and multiwavelength properties of LADUMA HI galaxies |
| thesis_degree_str | Master's |
| title | The automated detection and multiwavelength properties of LADUMA HI galaxies |
| title_full | The automated detection and multiwavelength properties of LADUMA HI galaxies |
| title_fullStr | The automated detection and multiwavelength properties of LADUMA HI galaxies |
| title_full_unstemmed | The automated detection and multiwavelength properties of LADUMA HI galaxies |
| title_short | The automated detection and multiwavelength properties of LADUMA HI galaxies |
| title_sort | automated detection and multiwavelength properties of laduma hi galaxies |
| topic | LADUMA MeerKAT Array |
| url | http://hdl.handle.net/11427/42708 |
| work_keys_str_mv | AT stockenstroomleyya theautomateddetectionandmultiwavelengthpropertiesofladumahigalaxies AT stockenstroomleyya automateddetectionandmultiwavelengthpropertiesofladumahigalaxies |