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dc.contributor.authorMcGill, Peter
dc.date.accessioned2021-10-22T06:15:34Z
dc.date.available2021-10-22T06:15:34Z
dc.date.issued2022-01-29
dc.date.submitted2021-08-09
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/329757
dc.description.abstractThis thesis is concerned with looking for and characterizing microlensing events in two places that are relatively unexplored. Leveraging astrometry from the Gaia satellite, I search for predicted close stellar alignments by lenses in the solar neighbourhood that will give rise to a microlensing event. Using Near-Infrared (NIR) photometry from the Vista Variables in the Via Lactea (VVV) survey, I extract microlensing events towards highly-extinct regions of the Galactic bulge. In both cases, I develop a Bayesian methodology to characterize the microlensing signals. In Chapter 1, I review the history of finding microlensing events both by predicting stellar alignments and by monitoring millions of stars. I describe two uses for these types of events; lens mass determination and probing structure of the Galactic bulge. In Chapter 2, I detail the microlensing signals and the methods which underpin the results presented in the rest of the thesis. In Chapter 3, I find a predicted microlensing event where the lens is a nearby white dwarf. Analysis of this event permitted a direct mass determination of the white dwarf which in turn allowed a test of the white dwarf mass-radius relationship. In Chapter 4, I present a search for predicted photometric microlensing events. For these events, I investigate combining prior astrometric information from Gaia with photometric follow-up data to extract the lens mass. In Chapter 5, I extend predicted microlensing searches using Gaia in combination with astrometry from the VVV. In Chapter 6, I critically examine the reliability of predicted microlensing events found with Gaia. I find that the majority of high-quality events expected to occur over Gaia’s life time are in fact spurious. Finally, in Chapter 7, I use machine learning to extract 1959 microlensing events from the VVV and I develop a Bayesian methodology to characterize their sparsely sampled signals.
dc.description.sponsorshipPhD studentship from the Sciences and Technologies Research Council (STFC)
dc.rightsAll Rights Reserved
dc.rights.urihttps://www.rioxx.net/licenses/all-rights-reserved/
dc.subjectgravitational lensing
dc.subjectmachine learning
dc.subjectBayesian statistics
dc.subjectastronomy
dc.subjectmicrolensing
dc.subjectastrometry
dc.subjectMilky Way
dc.titleGravitational Lensing in the Solar Neighbourhood and Towards the Milky Way Bulge
dc.typeThesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)
dc.publisher.institutionUniversity of Cambridge
dc.identifier.doi10.17863/CAM.77203
rioxxterms.licenseref.urihttps://www.rioxx.net/licenses/all-rights-reserved/
rioxxterms.licenseref.startdate2022-01-29
rioxxterms.typeThesis
dc.publisher.collegeDarwin
dc.type.qualificationtitlePhD in Astronomy
pubs.funder-project-idSTFC (1950369)
cam.supervisorEvans, Neil Wyn
cam.supervisorBelokurov, Vasily
cam.supervisor.orcidBelokurov, Vasily [0000-0002-0038-9584]


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