Vincoli alla distribuzione di materia oscura della Via Lattea con astrometria di alta precisione

This Thesis aims to determine the astrometric precision required to a future astrometric mission to study the dark matter (DM) halo of the Milky Way (MW) using hypervelocity stars (HVSs). We build upon the methodology developed by Gallo et al. (2022), who used mock observable distributions of HVSs to constrain the shape of the DM halo. We improve the method by identifying new effective observables for studying the DM halo shape. Specifically, we find that the tan- gential acceleration, at, in Galactocentric coordinates and a function, ̄vθ, of the Galactocentric latitudinal velocity enhance the performance of the method. We identify the main sources of uncertainty on HVS observables to be the distance, the radial velocity, the proper motion, the position on the plane of the sky and the magnitude. Each source of error is individually analyzed through mock data resampling to determine its impact on the method’s success rate. We test the method’s performance using real astrometric uncertainties from the Gaia mission. We constrain the necessary astrometric precision required to a future astrometric mission by testing the method with improved Gaia mission’s precision. Our find- ings indicate that an improvement of the Gaia DR5 precision by a factor of about 1000, corresponding to a precision on the parallax σω ∼ 0.3 μas for a faint object of G = 20 mag, is needed to obtain a success rate SR ≥ 62.0% in determining the correct shape of a triaxial DM halo.