Description du projet
Chercher des réponses dans les étoiles
La Voie lactée est la galaxie spirale barrée qui contient notre système solaire. Et notre soleil n’est qu’une des quelques 200 milliards d’étoiles qui la compose. Le projet VIA LACTEA, financé par l’UE, s’intéressera de près au processus de formation de la Voie lactée. Pour cela, il examinera ses principaux événements d’accrétion ainsi que la formation de son halo interne en utilisant des techniques informatiques de pointe. Puis, il étudiera l’impact des satellites connus. Le projet s’appuiera sur la carte tridimensionnelle de la Voie lactée établie par le satellite Gaia de l’Agence spatiale européenne, qui montre que les étoiles de notre galaxie ont une structure et une cinématique beaucoup plus complexes qu’on ne le pensait jusqu’ici. Les résultats de l’étude nous permettront de faire un pas de plus vers une meilleure compréhension de notre univers.
Objectif
The second data release of the Gaia satellite has revealed much complexity in the structure and kinematics of stars in the Milky Way than previously appreciated. In the disc, Gaia has shown that our Galaxy is still enduring the effects of a collision that set millions of stars moving like ripples on a pond. In the stellar halo, the data uncovered a large single debris structure pointing to a massive accretion event 10 billion years ago, at a time when the disc was in its infancy. Our basic assumptions of dynamical equilibrium and axisymmetry at the basis of nearly all mathematical models of the Galaxy are now falling short to make further progress on our inference on the Galaxy’s formation or the distribution of dark matter. Understanding the detailed time-dependent non-axisymmetric phase-space structure of the Galaxy would open new pathways to understand its detailed accretion history, potentially dating its most major perturbations. This proposal aims to explore the deep coupling between the stellar halo and the Milky Way disc and bulge, to gain new insights on the formation history of the Milky Way through its most major accretion events through a number of state-of-the-art computing techniques. Study 1 will look into studying the formation of the inner-halo through a combination of cosmological genetically modified (constrained) simulations and idealised simulations to constrain the mass and accretion time of the Gaia-Sausage progenitor galaxy (and its potential satellite population which came with it) as well as its impact on the formation of the ``thick disc'' and growth of the Galaxy past z~3-2. Study 2 will look into the impact of known satellites on the dynamical and chemical and age populations’ evolution of the Milky Way using both cosmological/isolated hydrodynamical simulations and idealised numerical N-body simulations, particularly focusing on the role of the Sagittarius dwarf in seeding the perturbations in the disc we see today.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
08007 Barcelona
Espagne