The Milky Way as key to understanding the inward transport of matter to the centre of galaxies

Descrizione del progetto

Il trasporto di materia verso l’interno del centro galattico

Il gas che si aggrega sui buchi neri supermassicci centrali alimenta i nuclei galattici attivi, influenzando l’evoluzione delle galassie. Tuttavia, abbiamo una scarsa comprensione di come il gas venga trasportato dalle scale galattiche fino alla sfera di influenza dei buchi neri. Il centro della Via Lattea offre un modello unico per studiare questo processo. Il progetto GalFlow, finanziato dal CER, utilizzerà nuovi set di dati e simulazioni per indagare la parte meno compresa del processo di trasporto, ovvero come il gas viaggia dalla zona molecolare centrale (CMZ) al buco nero centrale SgrA*. Il lavoro del progetto migliorerà la nostra comprensione della struttura e della dinamica del centro galattico e dei meccanismi di trasporto universali che operano in tutte le galassie.

Obiettivo

Gas accreting onto supermassive black holes that sit at the centres of galaxies fuels the most powerful engines in the universe, Active Galactic Nuclei, shaping the formation and evolution of their host galaxies. Yet, we have a poor understanding of how the gas is transported from typical galactic radii, R=several kpc, down to the area of influence of the black holes, less than a few pc. The centre of the Milky Way can be studied in much greater detail than any other galactic nucleus and is a Rosetta Stone to understand the physical processes that occur in all galaxies. Interstellar gas is transported from the Galactic Disc down to the central black hole SgrA* through a sequence of steps. The Galactic Bar performs the first step by efficiently transporting gas from the Disc (R=3kpc) down to the ring-like accumulation of gas known as the Central Molecular Zone (CMZ) at R=120pc. In the last few years I have led major theoretical efforts to understand and quantify this first step. However, these efforts have also demonstrated that the bar is ineffective in driving the gas further inwards. A long-standing question is how the gas continues from the CMZ to SgrA*. For the first time we have the possibility to answer this question thanks to new datasets and advances in numerical simulations. I propose here an unprecedented effort to solve this important problem through a unified analysis of all the relevant physical processes based on novel data and methodologies. I will combine recent and upcoming high-resolution astrometric and spectroscopic data with advanced stellar dynamical models to constrain the gravitational potential in the Galactic centre (GC). I will then use this potential to run cutting-edge numerical simulations to systematically quantify the contribution of all the mechanisms that can drive inward mass transport. This will solve the problem of the inward mass transport in the GC and will give us fundamental insights that can be applied to all galaxies.