The Galactic halo is the fossil record of the early history of our Galaxy. It is the best place to find not only the very first stars that formed in the Milky Way, but also in other galaxies that where then accreted into our home. Determining ages and chemical abundances of halo stars is therefore crucial to put timescales on the early formation of the Milky Way. Since my PhD times I have been testing methods to determine ages and chemical compositions of large samples of halo stars.

With my dear collagues Payel Das from Surrey University and Keith Austin from Texas Austin University, we have been finding efficient ways to identify accreted stars in the halo with the help of spectroscopic survey data and Gaia. Since my arrival in Chile, I have been taking advantage of the facilities at Las Campanas Observatory to take spectra of halo stars using the 6.5 Magellan twin telescopes.  These data are the ideal stellar playground for the PhD student at UDP, Danielle de Brito Silva.

The next challenges will be to find ways to put our findings in context with cosmological simulations. That long-term goal that started at my PhD will be accomplished thanks to the FONDECYT Regular grant I am Co-I with Patricia Tissera, from Pontificia Universidad Católica de Chile.