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How the Milky Way Built Its Disk

Final Report Summary - MW-DISK (How the Milky Way Built Its Disk)

The project set out to understand how the Galactic stellar disk, the main component of our milky way formed and evolved. This effort is part of making our on Galaxy a model organism for galaxy evolution as a whole. The project set out an observational and data modelling study to assemble an unprecedented data set about the ages, chemical abundances, distances and orbits of stars, and interpret this Galactic archeological record in terms of evolutionary scenarios. Broadly speaking, the project succeeded in all of its essential aspects, and exceeded the documented hopes and goals in quite a number of them.
We wchieved the first global empirical picture (as opposed to the previous local picture within 2kpc of the sun) of how the Galactic disk structure (radially, vertically) depends on the composition and ages of the stars. This work enables us to see for the first time how the entire disk grew inside out, gradually enriched at each radios and how extensively stars migrated in radius. This extensive radial migration has extensive consequences, which were orked out for the first time in this proposal: radial migration makes radial disk profiles look exponential and should lead to observable flaring of the outer disk (which we observe).
These results were obtained on the basis of some technical breakthroughs that we achieved in the context of this proposal: we showed how to get far better element abundances from stellar sprctra, using data-driven methods; we showed how to get stellar abundances from low-resolution spectra; we shoed how to get stellar ages from spectra of giant stars, a success that enables stellar age maps throughout the Galaxy. And we showed how to make precise 3D maps of the Milky Way´s stellar halo, using a novel approach to finding and modelling RR Lyrae stars with sparse lightcurve data. In numbers: 40 referred publications, 1000 citations by the end of the grant.