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New applications of statistics in astronomy and cosmology
Includes bibliographical references.
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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Department of Mathematics and Applied Mathematics
2015
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| _version_ | 1867611335027589120 |
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| access_status_str | Open Access |
| author | Lochner, Michelle Aileen Anne |
| author2 | Bassett, Bruce |
| author_browse | Bassett, Bruce Lochner, Michelle Aileen Anne |
| author_facet | Bassett, Bruce Lochner, Michelle Aileen Anne |
| author_sort | Lochner, Michelle Aileen Anne |
| collection | Thesis |
| description | Includes bibliographical references. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/12864 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | Department of Mathematics and Applied Mathematics |
| publisherStr | Department of Mathematics and Applied Mathematics |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/12864 New applications of statistics in astronomy and cosmology Lochner, Michelle Aileen Anne Bassett, Bruce Applied Mathematics Includes bibliographical references. Over the last few decades, astronomy and cosmology have become data-driven fields. The parallel increase in computational power has naturally lead to the adoption of more sophisticated statistical techniques for data analysis in these fields, and in particular, Bayesian methods. As the next generation of instruments comes online, this trend should be continued since previously ignored effects must be considered rigorously in order to avoid biases and incorrect scientific conclusions being drawn from the ever-improving data. In the context of supernova cosmology, an example of this is the challenge from contamination as supernova datasets will become too large to spectroscopically confirm the types of all objects. The technique known as BEAMS (Bayesian Estimation Applied to Multiple Species) handles this contamination with a fully Bayesian mixture model approach, which allows unbiased estimates of the cosmological parameters. Here, we extend the original BEAMS formalism to deal with correlated systematics in supernovae data, which we test extensively on thousands of simulated datasets using numerical marginalization and Markov Chain Monte Carlo (MCMC) sampling over the unknown type of the supernova, showing that it recovers unbiased cosmological parameters with good coverage. We then apply Bayesian statistics to the field of radio interferometry. This is particularly relevant in light of the SKA telescope, where the data will be of such high quantity and quality that current techniques will not be adequate to fully exploit it. We show that the current approach to deconvolution of radio interferometric data is susceptible to biases induced by ignored and unknown instrumental effects such as pointing errors, which in general are correlated with the science parameters. We develop an alternative approach - Bayesian Inference for Radio Observations (BIRO) - which is able to determine the joint posterior for all scientific and instrumental parameters. We test BIRO on several simulated datasets and show that it is superior to the standard CLEAN and source extraction algorithms. BIRO fits all parameters simultaneously while providing unbiased estimates - and errors - for the noise, beam width, pointing errors and the fluxes and shapes of the sources. 2015-05-26T14:12:42Z 2015-05-26T14:12:42Z 2014 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/12864 eng application/pdf Department of Mathematics and Applied Mathematics Faculty of Science University of Cape Town |
| spellingShingle | Applied Mathematics Lochner, Michelle Aileen Anne New applications of statistics in astronomy and cosmology |
| thesis_degree_str | Doctoral |
| title | New applications of statistics in astronomy and cosmology |
| title_full | New applications of statistics in astronomy and cosmology |
| title_fullStr | New applications of statistics in astronomy and cosmology |
| title_full_unstemmed | New applications of statistics in astronomy and cosmology |
| title_short | New applications of statistics in astronomy and cosmology |
| title_sort | new applications of statistics in astronomy and cosmology |
| topic | Applied Mathematics |
| url | http://hdl.handle.net/11427/12864 |
| work_keys_str_mv | AT lochnermichelleaileenanne newapplicationsofstatisticsinastronomyandcosmology |