Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

This proposal covers research programs in statistical studies of astrophysical turbulence and in the theory of the filamentary Cosmic Web and its role in the properties of galaxies and clusters of galaxies.

Turbulence and Magnetic fields play critical role in many of the key astrophysical processes. Determining energy distribution in turbulent motions, strength, orientation and scaling of the magnetic fields, characteristics scales of energy injection and dissipation, relative strength of incompressible and compressible modes are of vital importance for understanding fundamental astrophysical process such as star formation, heat transport in interstellar and intra-cluster medium, acceleration of cosmic ray. In our Galaxy, in other galaxies, or in clusters of galaxies, magnetic fields are found to be carried around by complex turbulent motions of plasma, which results in characteristic correlations in the intensity and polarization of light emitted as Doppler shifted spectral lines or diffuse synchrotron radiation. Disentangling the quantitative properties of the magnetized turbulence from such observations is a complex task. We are developing rigorous statistical methods, based on modern models of the magnetized turbulence, and for a variety of observable data, to accomplish it.

Cosmologists are now confident in the overall picture of structure formation in our Universe. The complexity of our Universe came from tiny quantum fluctuations of matter at the very early era when the Universe rapidly inflated. Inhomogeneities later grew under the force of gravity into stars, galaxies and, at large scales, the galactic Web, leaving along the way the imprint on the Cosmic Microwave Background. At the earlier epoch the filamentary Web of dark matter and gas distribution was shown to affect the formation of the galaxies, while at present time it defines the inter-cluster environment. We shall study theoretically and numerically the connectivity of the filamentary pattern as it evolves from initial conditions to galactic and then cluster scales. Our goal is to answer questions such as how many filaments join the cluster, does this depend on the cluster properties, does it tell us how cluster was assembled, how long are filament arms, do filaments form a connected network or are disjoint, how these parameters evolve in time depending on a cosmological model; and, in this way, obtain a more complete description and understanding of the structure in the Universe. We will also investigate the effect being in filamentary environment has on galaxy properties, and in particular their spin by working towards detailed statistical theory of halo spin distribution within the large scale structures, that would be beneficial for understanding galaxy formation and for interpretation of the future galactic surveys.