The automated detection and multiwavelength properties of LADUMA HI galaxies

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dc.contributor.advisorDelhaize, Jacinta
dc.contributor.advisorJarvis, Matt
dc.contributor.authorStockenstroom, Leyya
dc.date.accessioned2026-01-28T06:50:26Z
dc.date.available2026-01-28T06:50:26Z
dc.date.issued2025
dc.date.updated2026-01-28T06:44:13Z
dc.description.abstractIn 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.
dc.identifier.apacitationStockenstroom, L. (2025). <i>The automated detection and multiwavelength properties of LADUMA HI galaxies</i>. (). University of Cape Town ,Faculty of Science ,Department of Astronomy. Retrieved from http://hdl.handle.net/11427/42708en_ZA
dc.identifier.chicagocitationStockenstroom, Leyya. <i>"The automated detection and multiwavelength properties of LADUMA HI galaxies."</i> ., University of Cape Town ,Faculty of Science ,Department of Astronomy, 2025. http://hdl.handle.net/11427/42708en_ZA
dc.identifier.citationStockenstroom, L. 2025. The automated detection and multiwavelength properties of LADUMA HI galaxies. . University of Cape Town ,Faculty of Science ,Department of Astronomy. http://hdl.handle.net/11427/42708en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Stockenstroom, Leyya AB - 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. DA - 2025 DB - OpenUCT DP - University of Cape Town KW - LADUMA KW - MeerKAT Array LK - https://open.uct.ac.za PB - University of Cape Town PY - 2025 T1 - The automated detection and multiwavelength properties of LADUMA HI galaxies TI - The automated detection and multiwavelength properties of LADUMA HI galaxies UR - http://hdl.handle.net/11427/42708 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/42708
dc.identifier.vancouvercitationStockenstroom L. The automated detection and multiwavelength properties of LADUMA HI galaxies. []. University of Cape Town ,Faculty of Science ,Department of Astronomy, 2025 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/42708en_ZA
dc.language.isoen
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Astronomy
dc.publisher.facultyFaculty of Science
dc.publisher.institutionUniversity of Cape Town
dc.subjectLADUMA
dc.subjectMeerKAT Array
dc.titleThe automated detection and multiwavelength properties of LADUMA HI galaxies
dc.typeThesis / Dissertation
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMSc
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