Abstract
dc:description.abstractThe content of this thesis derives from three projects conducted during my Ph.D, focusing on both the Milky Way and the Magellanic Clouds. I deploy long period variables, especially Miras, as chronometers to study the evolution of Galactic structure over stellar age. I study red giants in the Magellanic Clouds, assign them photometric metallicities and map large scale trends both in their chemistry and proper motions. In Chapter 1 I provide an overview of the historical observations that underpin our current understanding of the Galactic components. Specifically, I detail those pertaining to the Galactic bulge, the Galactic disc and the Magellanic Clouds as it is these that constitute the main focus of the work in this thesis. In Chapter 2 I collate a sample of predominately oxygen-rich Mira variables and show that gradients exists in their pulsation period profiles through the Galaxy. Under the interpretation that the period of Miras correlates inversely with their stellar age, I find age gradients consistent with the inside-out disc formation scenario. I develop such analysis further in Chapter 3: seizing on the Miras provided by Gaia DR2, I observe them to trace the Galactic bulge/bar and disc. With the novel ability to slice both components chronologically at once, the old disc is seen to be stubby; radially constricted and vertically extended. The younger disc is vertically thinner and more extensive radially, providing further observational evidence for inside-out formation of the Milky Way disc. The longer period and hence younger bulge Miras show a clear bar-like morphology bearing the classic X-shape. The old, short period bulge Miras appear to constitute a separate population, decoupled from the inclined bar with little evidence for having buckled. Chapter 4 details a chemo-kinematic analysis of red giants residing in the Magellanic Clouds. I utilise optical and infra-red photometry to assign photometric metallicity estimates to the giants. The metallicity structure in the larger Cloud correlates with known stellar over-densities induced from historic perturbations. I observe the smaller Cloud to be disrupting, identifying stellar debris trailing the dwarf.
Degree
thesis:*- Name dc:type.qualificationname
- Doctor of Philosophy (PhD)
- Level dc:type.qualificationlevel
- Doctoral
- Grantor dc:publisher.institution
- University of Cambridge
- Year dc:date.issued
- 2021
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Grady, James
- Advisors dc:contributor.advisor
-
- Evans, Neil
- Belokurov, Vasily
Subjects
dc:subject × 4Rights
dc:rightsIdentifiers
dc:identifier.*- Author Identifier
- 0000-0002-0038-9584
- OAI identifier oai:identifier
- oai:www.repository.cam.ac.uk:1810/322979