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The automated detection and analysis of gravitational microlensing events
Thesis (MEng)--University of Stellenbosch, 2000.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867614009174261760 |
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| access_status_str | Open Access |
| author | Van Rooyen, Ruby |
| author2 | Herbst, B. M. |
| author_browse | Herbst, B. M. Van Rooyen, Ruby |
| author_facet | Herbst, B. M. Van Rooyen, Ruby |
| author_sort | Van Rooyen, Ruby |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--University of Stellenbosch, 2000. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/51942 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:13.015Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/51942 The automated detection and analysis of gravitational microlensing events Van Rooyen, Ruby Herbst, B. M. Menzies, J. Weber, D. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. MATLAB Image processing Gravitational lenses Astronomy -- Observations -- Observations Microlensing Dissertations -- Electronic engineering Theses -- Electronic engineering Thesis (MEng)--University of Stellenbosch, 2000. ENGLISH ABSTRACT: In this thesis we addressed some issues concerning the automation of the detection, processing and the analysis of gravitational microlensing events, which are currently being used in the search for extra-solar planets. We were provided with a series of data images containing a microlensing event. Using these images we address several practical problems: registration, background subtraction and some PSF modelling. Registration is accomplished by using the intersection points of circular arcs drawn around stellar objects. After which the influence of the sky background is removed by using the watershedding algorithm and plane fitting. Our analysis is based on relative brightness - to counter seeing, the brightness of stars are calculated by isolating the objects from the background and summing over the area. A brightness variation curve is plotted and the trend of the lensing event and the posi tion of a blip are extracted using wavelets, calculating general trends and LOESS. The trend of the brightness variation curve can be used for both identification and classification of various events. It can also be used for the identification and classification of variable stars. Blip analysis is used to detect the presence of a planet (or dark body) in the vicinity of the source. AFRIKAANSE OPSOMMING: Hierdie tesis beskryf tegnieke om die identifikasie, prosessering en analise van gravitasie mikro-lens gebeure te outomatiseer. Die analise van hierdie gebeure is belangrik aangesien dit gebruik word vir die opsporing van planete buite ons sonnestelsel. Om gebruik te maak van 'n reeks beelde wat een van hierdie gebeure vertoon moet ons die volgende probleme aanspreek: beeld registrasie, verwydering van die agtergrond en die modulering van die verspreiding van die lig van 'n puntbron deur die atmosfeer. Ons verkry registrasie deur die berekening van die snypunte van sirkels met middelpunte by sekere voorwerpe op die beeld. Na registrasie kan ons die invloed van die agtergrond bepaal deur gebruik te maak van die waterskeidingsalgoritme. Dit stelons in staat om die relatiewe helderheid van die voorwerpe ondersoek deur die voorwerpe te isoleer en te sommeer oor die area van 'n voorwerp. 'n Grafiese voorstelling van die helderhede dui vir ons die relatiewe variasies in die helderhede van die mikrolens objek tussen die beelde aan. Ons ondersoek die vorm van die kromme asook die moontlike voorkoms van 'n 'blip' deur middel van wavelet analiese en die LOESS metode. Die vorm van die kromme word gebruik vir die identifikasie en klassifikasie van die verskillende mikro-lens gebeure en kan uitgebrei word om ook veranderlike sterre te ondersoek. Die teenwoordighied van 'n 'blip' op die data wys op die moontlik teenwoordigheid van 'n planeet nabyaan die bron wat ons ondersoek. 2012-08-27T11:34:46Z 2012-08-27T11:34:46Z 2000-12 Thesis http://hdl.handle.net/10019.1/51942 en_ZA Stellenbosch University 83 p. : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | MATLAB Image processing Gravitational lenses Astronomy -- Observations -- Observations Microlensing Dissertations -- Electronic engineering Theses -- Electronic engineering Van Rooyen, Ruby The automated detection and analysis of gravitational microlensing events |
| title | The automated detection and analysis of gravitational microlensing events |
| title_full | The automated detection and analysis of gravitational microlensing events |
| title_fullStr | The automated detection and analysis of gravitational microlensing events |
| title_full_unstemmed | The automated detection and analysis of gravitational microlensing events |
| title_short | The automated detection and analysis of gravitational microlensing events |
| title_sort | automated detection and analysis of gravitational microlensing events |
| topic | MATLAB Image processing Gravitational lenses Astronomy -- Observations -- Observations Microlensing Dissertations -- Electronic engineering Theses -- Electronic engineering |
| url | http://hdl.handle.net/10019.1/51942 |
| work_keys_str_mv | AT vanrooyenruby theautomateddetectionandanalysisofgravitationalmicrolensingevents AT vanrooyenruby automateddetectionandanalysisofgravitationalmicrolensingevents |