Gaia DR4 is planned for December 2026, covering the five years of nominal Gaia mission, and will include 'everything'. It will consist of more than 140 tables and of the order 500 TB of data. We give a brief overview of the various data products and how they are organized. With respect to Gaia DR3, the uncertainties will improve significantly and the release now includes the epoch data for...
While it is in general preferable to work with parallaxes instead of distances, some applications may make a conversion from parallaxes to distances desirable. At low signal-to-noise levels random noise may however cause the observed parallax to become negative. The conversion from parallax to distance has therefore to take the non-negativity of the true parallax, and distance, properly into...
Brief presentation on some new results of the long bar morphology using several stellar catalogues. An short extrapolation of what could be expected using NIR astrometric data will be given.
The Milky Way’s (MW) spiral structure has been longly studied using several tracers; however, it is not unambiguously determined yet. We address this by combining a hydrodynamical simulation and observational data.
In our simulation, stellar populations as old as 11Gyr and with velocity dispersions up to ~90km/s have overdensities coincident with the youngest spiral arms at all times. The...
Within the Local Arm Structure project we investigate the three-dimensional distribution and vertical kinematics of young tracers in the Orion (Local) arm using Gaia astrometry and recent catalogues of open clusters and star-forming regions. Building on our results in Vertical kinematics of the young Galactic clusters (Alfaro, Sánchez-Gil & Elmegreen 2025, MNRAS, doi:10.1093/mnras/staf155), we...
I will present a brief overview of the ChronoGal project which has recently been awarded an ERC advanced grant.
Despite the fundamental role of the star formation history (SFH) and the initial mass function (IMF) in describing the Milky Way—and their intrinsic correlation—their consistent and robust determination remains challenging. The unprecedented astrometric and photometric precision of Gaia provides a unique opportunity to address this long-standing problem. I will present a new implementation of...
Gaia data provide a detailed snapshot of the local structure of our Galaxy. However, to understand the global dynamical structure of the Milky Way and its time evolution, it is essential to compare observation data with theoretical models. In this context, I have been using high-resolution N-body simulations as theoretical counterparts of the Milky Way. Recent advances in GPU computing enable...
