Metallicity gradients in the resolved redshift desert

Galaxy metallicity gradients reveal the chemical structure of galaxies providing insight on how galaxies are formed. Yet a tension exists between measured metallicity gradients of galaxies in the local universe, showing a clear negative slope with radius, and galaxies in the early universe, showing flat or even inverted metallicity gradients. While some theories have suggested physical reasons for this evolution, others have claimed it is simply an observational bias due to poor resolution. However, during the last 6 Gyrs where the evolution is expected to be strongest there have been few studies due to the lack of suitable integral field spectrographs to resolved galactic emission lines ratios. With the recent state of the art blind MUSE surveys from the Very Large Telescope in Chile it is now possible to study the evolution of metallicity gradients over this key epoch testing theoretical models and connecting to both the oldest galaxies and those in our cosmic neighbourhood.

In this project the student would (1) establish a sample from the MUSE surveys that have suitable emission lines to measure metallicity gradients, (2) measure metallicity gradients using a variety of emission line diagnostics, (3) explore trends with cosmic time comparing to current model predictions, (4) investigate the issues arising from resolution effects. The student taking on this project is expected to familiarise themselves with the basic principles of emission-line spectroscopy and acquire the skills to successfully analyse the data.

For further details please contact the project supervisor.