We are an International Team in the field of space sciences on the topic of deconstructing the assembly history of galaxies with chemical orbit-tagging methods.

In galactic astrophysics we typically only observe properties of the galaxy at present day, and it has not been possible to recover this invisible past history of a galaxy’s mergers and star formation from typical ground or space-based observations of galaxies. Therefore, current state-of-the art imaging and spectroscopic analysis techniques are unable to untangle the memory of how a galaxy was assembled from the wealth of existing space-based observational data.

Our group has developed the unique tools to do this for the first time, with our innovative population-orbital decomposition techniques, which leverages the dynamical and stellar population “memory” encoded in the light and orbital motions of stars, to re-construct the build-up of individual galaxies. These techniques combine the long dynamical memory of how stars orbit in the galaxy’s gravitational potential, together with new models for recovering the ages of stars which populate the orbits. This methodology is able to extract orders of magnitude more information from current ground and space-based observations of galaxies – which means we also need to work with computer science experts on how to optimize and efficiently apply our methods to the abundance of observational data. The multi-disciplinary approach we are pioneering therefore necessitates close collaboration and synergy between researchers working on different subfields of space science topics (computer science experts, numerical dynamical modelling techniques, analytic theoretical models of how galaxies’ stars and gas evolve).