Madeleine McKenzie

PhD Student

Australian National University

Biography

PhD student at the Research School of Astronomy and Astrophysics at the ANU. Bok Prize winner 2021. Bachelor of Physics and Computer Science, Master of Astrophysics from UWA/ICRAR My project aims to quantify the relationship between different elements on the periodic table from cluster to galactic scales. This will integrate with Astro 3D's science goal of "What is the origin of matter and the periodic table elements" and will benefit the GALAH and First Stars projects. I will leverage the power of inhomogeneous mixing of stellar yields to reveal star formation on both the smallest and largest scales. For the small scale, I will analyse high-resolution spectra of M 22; a very metal-poor Globular Cluster that may be the remnant of a dwarf galaxy cannibalised by the Milky Way. High precision differential abundance measurements will expose metallicity correlations within the cluster and isotopic analysis can set constraints on the masses of AGB stars responsible for these patterns. This will be the first time isotopic analysis has ever been performed at such a low metallicity and will provide a unique view of stellar yields in the early Universe. For larger scales, I will build a theoretical model using the stellar population synthesis code SLUG to predict how different elements within a galaxy correlate with one another. Recent studies have demonstrated the power of cross-element correlation, which is more sensitive to hidden structure than dispersions alone. SLUG will test whether stochastic inhomogeneous mixing of the ISM will imprint on the correlation of abundances, revealing fundamental subgrid physics. I will take the results of my chemical models and compare them with the GALAH sample. This will push chemical tagging to limits never before seen to probe the engines that drive our Galaxy's evolution.