GALBAR

GALBAR is a collaborative research project between the Strasbourg Astronomical Observatory and Institut d’Astrophysique de Paris bringing together diverse expertise on galaxy simulations and theoretical galactic dynamics, to tackle the longstanding and surprisingly unresolved question of bar formation in galaxies. Galactic bars are a crucial ingredient in the secular evolution of disc galaxies, as they can interact with their stellar, gaseous, and dark matter components. Bars are very common in the local Universe, while their frequency decreases at earlier cosmic times as revealed by current observations. In spite of this quasi-ubiquity and decades of research, the physics regulating bar formation, survival, or inhibition remains poorly understood. Analytical approaches have been instrumental in providing considerable insight into the structure and dynamics of bars since the seminal works in the early 70’s. However, interaction with the dark matter halo and the dissipative gaseous component make bars much more complex than in purely self-gravitating stellar discs, and poorly understood. This impacts modern cosmological simulations which in spite of being nowadays capable of reproducing a large number of observed galaxy properties, such as disc morphology, get the bars wrong, both in terms of their frequency and their internal properties. Finding the underlying reason for this mismatch is a daunting task due to the diversity of numerical methods, resolution, and sub-grid recipes employed. We therefore propose an innovative approach consisting of combining different theoretical and numerical approaches to bar formation and confronting them to reach a holistic theoretical framework of the physics of bar formation. The proposed research project will significantly contribute to advancing our understanding of the full life-cycle of galactic bars and has the ambition to elucidate the `missing bar problem’ shared by modern high-resolution cosmological simulations.