Galactic stellar populations are good tracers of the history of the Milky Way. Their study via Gaia astrometric and photometric data should allow to pinpoint the star formation history (SFH) in the disc and halo in a self-consistent dynamical model. Population synthesis models are efficient tools to measure the SFH from the distribution of the stars in the Hess diagram, thanks to different...
The Gaia mission has produced an extraordinary amount of high quality photometric data for the whole sky and has contributed dramatically to advancing our understanding of the Milky Way. In particular, its data can be used to calibrate population synthesis models of our galaxy, aiming to reduce the gap between simulations and observations.
We present here a study of the star formation...
The Milky Way (MW) experienced several merger events which left their imprints on the stellar halo. In particular, it is known that a major merger happened during the Galaxy’s first Gyrs. In order to fully understand the effects of such an event, we need to know the chemical and dynamical characteristics of the young MW, i.e. before the major merger event, and the accreted satellite. For this...
Determining the circular velocity curve of a galaxy is a powerful tool for studying its overall properties. One can fit a potential and determine the dark matter distribution and density and the virial mass of the system.
One way of determining the rotation curve is through Jeans equations (Eilers et al. 2019, Ou et al. 2023). However, when using Jeans equations one needs to assume...
New 3D kinematic maps are derived based on Gaia DR3 proper motions and line-of-sight velocities for red giant branch stars, but now, unlike those published in Gaia Collaboration, Drimmel, Romero-Gómez+2022, taking into account the correlations between the proper motions, which contribute to the correlations between the derived kinematic variables. The large-scale correlations between the...
A-type stars are intrinsically bright, moderately numerous and kinetically warm. They trace the Galactic disk evolution at intermediate ages (0.3-1.0 Gyr), so they fill the gap between younger OB stars and older red giants. We present a catalogue of A-type stars selected in the northern Galactic plane (30º≤l≤215º and |b|≤5º) using photometry from the INT Galactic Plane Survey (IGAPS). It...
The vertical phase-space spiral (snail) is a direct sign of dis-equilibrium of Milky Way's disc. Nevertheless, the wrapping of the phase snail contains the information of the vertical potential. We propose a novel method to measure the vertical potential utilizing the intersections between the snail and $z$/$V_{z}$ axes, for which we know the maximum vertical heights ($Z_{max}$) or the maximum...
We use the Besançon Galaxy Model Fast Approximate Simulations (BGM FASt) framework together with the Approximate Bayesian Computation (ABC) algorithm to derive the posterior probability distribution function of the parameters defining the initial mass function (IMF) and the star formation history (SFH) in the solar neighbourhood. We propose new strategies to unveil the influence of some BGM...
Age is arguably the stellar fundamental parameters that is most difficult to obtain for most stars. Over the last few years, many studies have found empirical relationships between the abundance of a star and its isochrone age, known as chemical clocks. We present a new catalogue of spectroscopic stellar ages for 180,000 red-giant stars observed by the APOGEE survey with a median statistical...
