Astronomy Tea Talk

Monday, March 20, 2023
4:00pm to 5:00pm
Add to Cal
Online and In-Person Event
The Internal Metallicity Structure of Galaxies: Maths, Explosions, and the Limits of Detectability
Benjamin Metha, University of Melbourne,

The metallicity of a galaxy is set by its gas-phase physics: how is metal-poor gas accreting into a galaxy, how often are stars born, and how well are the products of star-formation mixed into their local environments? With data from high-resolution spectroscopic surveys, we can see that galaxies in the local Universe show significant deviations in metallicity from a simple linear trend, allowing us to directly see local metallicity enrichment and dilution events on scales below 100pc. This talk comes in two parts, and focuses on how this knowledge can help us understand how the internal metallicity distributions of galaxies change throughout cosmic time. In the first part, I will explore what the distribution of Gamma-Ray Bursts, a group of extremely bright transients that can be visible from z>6, can tell us about the chemical structure of high-z galaxies in cosmological simulations. In the second part, I introduce geostatistics, a family of mathematical tools and techniques that are useful for creating 2D predictive models of a galaxy's metallicity structure from noisy, incomplete data, and discuss the challenges associated with applying these methods to high-redshift galaxies recently observed by JWST.

For more information, please contact Junhan Kim by email at or visit