Solidifying what is known about calibration artefacts and the development of an educational tool to assist in the teaching of interferometric imaging

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dc.contributor.advisorGrobler, Trienkoen_ZA
dc.contributor.advisorLudick, Danieen_ZA
dc.contributor.authorJackson, Jason Peteren_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Computer Science.en_ZA
dc.date.accessioned2023-02-28T14:25:29Zen_ZA
dc.date.accessioned2023-05-18T07:11:39Zen_ZA
dc.date.available2023-02-28T14:25:29Zen_ZA
dc.date.available2023-05-18T07:11:39Zen_ZA
dc.date.issued2023-03en_ZA
dc.descriptionThesis (MSc)--Stellenbosch University, 2023.en_ZA
dc.description.abstractENGLISH ABSTRACT: Radio interferometers are arrays of radio antennas that work together to capture celestial radio emission. Imaging involves transforming the raw measurements made by these so-called interferometers into images of the radio sky. The first contribution of this thesis is the creation of an educational tool that utilizes the Transient Array Radio Telescope (TART). This tool can be used to teach radio interferometric imaging to undergraduate and postgraduate students. Calibration is the act of trying to correct for the effects that may have interfered with the celestial radio emission that an interferometer receives. Calibration artefacts or systematics are inadvertently created when we calibrate our instrument. Calibrating with an incomplete sky model in particular can create artefacts called ghosts. Ghosts are spurious sources that do not truly exist. A second contribution of the thesis is the creation of a scientific tool with which calibration artefacts can be studied. This tool is then used to investigate what artefacts form when a single extended source is only partially modelled (with a point source model). The results of this study show that for the aforementioned extended use-case ghosts become extended sources themselves. They also alter the original extended source in various ways. The original source takes on the same flux scale as the source in the calibration model and its profile changes; it becomes more point-like. The shorter baselines are also more severely affected than the longer baselines are and in contrast to previous studies for this particular setup the number of antennas does not impact the severity of the artefacts which are created.en_ZA
dc.description.abstractAFRIKAANS OPSOMMING: ’n Radiointerferometer is ’n skikking van radio antennas wat saam werk om buiteaardse radio golwe waar te neem. Beeldskepping vind plaas wanneer die rou metings wat radiointerferometers maak omskep word in beelde van die radiohemelruim. Die eerste bydrae van die tesis behels die skepping van ’n onderrigstoepassing wat van die Kortstondige Skikking Radioteleskoop (KSRT) gebruik maak. Hierdie toepassing kan gebruik word om adiointerferometriesebeeldskepping te verduidelik aan voorgraadse en nagraadse studente. Kalibrasie is die taak waarmee mens probeer om die ongewenste effekte wat geïnduseer word op die metings van ‘n interferometer te verwyder. Kalibrasie artefakte of ongewensthede word gegeneereer wanneer ’n interferometer gekalibreer word. Om meer spesifiek te wees, wanneer mens kalibreer met ‘n onvolledige model van die hemelruim dan vorm daar artefakte wat bekend staan as spookbronne. Spookbronne is ongewenstebronne wat nie werklik bestaan nie. ’n Tweede bydrae van hierdie tesis is die skepping van ‘n wetenskaptoepassing waarmee kalibrasie artefakte bestudeer kan word. Die toepassing word dan ook gebruik om die artefakte wat vorm wannneer ’n uitgebruidebron gemodelleer word met ’n puntborn te bestudeer. Die bevindinge van die studie bewys dat die spookbron wat vorm in die geval uitgebreid is, en nie net ’n puntbron is nie. Verder word daar bewys dat die spookbron ook die eienskappe van die oorspronklike bron op verskeie manier verander. Eerstens neem die oorspronklike bron dieselfde vloedwaarde as die bron in die kalibrasie model aan. Verder verander die profiel van die oorspronklike bron, dit word meer puntagtig. Die korter basisvektore word ook meer beïnvloed as wat die langer basisvektore beïnvloed word. Laastens word daar bevind dat in kontras met vorige studies die helderheid van die artefakte wat vorm nie afhang van die aantal antennas in die skikking nie. af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxviii, 134 pages : illustrations.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/127243en_ZA
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectRadio Interferometry Calibration Artefactsen_ZA
dc.subject.lcshRadio interferometersen_ZA
dc.subject.lcshCalibrationen_ZA
dc.subject.lcshAstronomy -- Observationsen_ZA
dc.titleSolidifying what is known about calibration artefacts and the development of an educational tool to assist in the teaching of interferometric imagingen_ZA
dc.typeThesisen_ZA
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