Sample selection effects in laduma stacking experiments
| dc.contributor.advisor | Elson, Edward | |
| dc.contributor.author | Gwebushe, Lwandile | |
| dc.date.accessioned | 2024-03-19T14:23:32Z | |
| dc.date.accessioned | 2024-10-30T10:23:34Z | |
| dc.date.available | 2024-03-19T14:23:32Z | |
| dc.date.available | 2024-10-30T10:23:34Z | |
| dc.date.issued | 2023 | |
| dc.description | >Magister Scientiae - MSc | en_US |
| dc.description.abstract | This study explores the impact of selection effects introduced by input optical cata-logues on high-redshift stacking experiments. Using the Hi stacking technique, the Hi content of LADUMA synthetic data cubes is analyzed within the redshift range of 0.7 < z < 0.758. The focus is on galaxies with stellar masses of M⋆/M⊙ ≥ 108.5. The investigation reveals several key findings. Firstly, the input optical catalogues displays biases towards specific galaxy types, including those with lower stellar masses, lower star-formation rates, lower specific star-formation rates, galaxies in groups, and red galaxies. These biases can lead to higher confusion rates in stacked spectra, emphasizing the need for appropriate correction methods to avoid overestimation in subsequent quantitative analyses. Secondly, the environmental impact on Hi gas properties is examined by comparing group galaxies and non-group galaxies. Non-group galaxies exhibit higher Hi richness and Hi gas fractions compared to group galaxies. Correlations between Hi properties and star-formation/stellar mass properties are observed, indicating that lower mass galaxies are relatively inactive within their environments and are at an earlier stage of evolution. The study also addresses the correction of confusion rates in stacked spectra. While a correction method is implemented, it is found to result in overestimated Hi deple-tion timescales. Criticism is directed towards the use of this method, stressing the importance of employing accurate and robust approaches to correct for confusion rates and ensure precise estimation of galaxy properties. | en_US |
| dc.identifier.uri | https://hdl.handle.net/10566/16654 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of the Western Cape | en_US |
| dc.rights.holder | University of the Western Cape | en_US |
| dc.subject | Galaxies: ISM | en_US |
| dc.subject | Stacked spectra | en_US |
| dc.subject | University of the Western Cape | en_US |
| dc.subject | Hi mass | en_US |
| dc.subject | laduma | en_US |
| dc.title | Sample selection effects in laduma stacking experiments | en_US |
| dc.type | Thesis | en_US |