Angular momentum transfer in galaxy formation and evolution

In a nutshell

The project is dedicated to follow angular momentum within structures over a wide range of scales, to trace galaxy formation and the history of mass assembly. Angular momentum is a key parameter to determine galaxy morphology and kinematics. In the local universe, it can serve to describe the Hubble sequence. Structures acquire angular momentum through tidal torques before their collapse in the early universe. The subsequent evolution may help to understand galaxy formation, although numerical models fail to reproduce large disk galaxies today, by lack of angular momentum. The project will focus on three areas:

• detailed angular momentum transfer due to non-axisymmetric features, such as bars and spirals, in early galaxies, submitted to internal dynamical processes, but also external matter accretion
• census of angular momentum exchanges during galaxy interactions, transformation from orbital to internal spin, and exchange between the various components, role of the environment on the density of angular momentum, through cosmic filaments, and formation of large-scale structures
• efficient fueling of super-massive black holes (SMBH) in the early universe, through angular momentum transfer, and study of complex feedback processes, in particular around bright cluster galaxies, at the centre of cooling flows.

To address these three issues, we will carry on complementary simulations, with the best state-of-the art codes, tree-SPH, multi-phase including sticky particles, or Eulerian AMR code. The complex baryonic physics will be modelled, and comparisons made while varying methods and physical parameters. The highest resolution will be used to trace angular momentum transfer and resonances in idealised galaxies, but boundary conditions will be obtained from cosmological large-scale simulations.

At every step, the simulations will be confronted to observations, thanks to modern statistical surveys already public, or on-going, in which members of the team participate actively (SDSS, Sauron, Atlas3D, Goods, IRAM & Herschel key projects). New key projects will also be initiated on IRAM and ALMA. The project will also provide observers with simulation results, presented in a form similar to observations, through a query-able data base using the Virtual Observatory tools.

As scientific outcome, the project will illuminate many fundamental aspects of galaxy formation and evolution, and enlighten some current conundrums, such as the angular momentum catastrophe, the bimodality of galaxy in colour/magnitude, the downsizing of star formation and nuclear activities, or the existence of SMBH as early as z=6.