Dark Matter (DM) is the most long-standing cosmological puzzle. Its existence was first postulated by F. Zwicky in the thirties in order to reconcile the observed high velocities of Galaxies with Newtonian dynamics. Acting as a sort of cosmic glue, it enables Galaxies to be bound within clusters of galaxies. In the seventies similar conclusion was reached from Galactic rotation curves, showing that stars orbit too fast in Galaxies compared to the Keplerian prediction. The presence of DM halos, extending well beyond the galactic disk, would again reconcile observations with Newtonian dynamics. Today the most favoured solution is that DM is made of a new elementary particle, none of the known ones within the Standard Model of Particle Physics.
However, so far we have only tested gravitational effects of DM, that plays a crucial role not only to explain the dynamics of stars and Galaxies, as mentioned above, but also the origin and formation of Large Scale Structure and the temperature anisotropies of the Cosmic Microwave Background. However, the specific nature of DM is still unknown. For example its mass can be anything between ~10-30 eV, as in the case of light axions, and the mass of macroscopic objects such as primordial black holes. In the last years, astronomical observations have highlighted interesting properties of so called DM sub halos hosting Dwarf Galaxies. These are DM-dominated self-gravitating systems orbiting within DM galactic halos with a mass typically of ~109 solar masses. The dwarf galaxies rotation curves are in disagreement with the results from numerical simulations assuming a traditional Cold DM scenario (DM that was non relativistic at the time of matter-radiation equality ~70,000 years after the Big Bang). These strongly depend on the DM phase-space distribution whose calculation on these scales is, however, plagued by large theoretical uncertainties. The disagreement between current N-body simulations and astronomical observations has then stimulated DM scenarios beyond the traditional Cold DM one, such as Warm DM and Self Interacting DM.
In this project our main goal is the calculation of the DM phase-space distribution taking into account important effects described by more sophisticate kinetic approaches than traditional ones, such as so called BBGKY hierarchy, where three body correlation effects are taken into account, effects that cannot be neglected in self-gravitating systems due to the long range nature of gravity. This requires the introduction of novel computational approaches based on Quantum Field Theories methods. We also aim at studying specific DM scenarios in particular very heavy decaying DM scenarios in connection with the data from the Ice-Cube neutrino detector.More ambitiously the project would also aim at identifying new strategies to constraint the DM mass range and more generally its properties. The project is a genuine Astro-Particle Physics projects, at the interface between Astronomy and Particle Physics. Strong computing skills are required together with basic knowledge of Particle Physics, Quantum Field Theory, Statistical mechanics and Astrophysics.
If you wish to discuss any details of the project informally, please contact Pasquale Di Bari, SHEP research group, Email: [email protected]
, Tel: +44 (0) 2380 59 3918.
URL for home page of supervisor (and optionally co-supervisor):
Pasquale Di Bari home page: http://www.southampton.ac.uk/~pdb1d08/
This project is run through participation in the EPSRC Centre for Doctoral Training in Next Generation Computational Modelling (http://ngcm.soton.ac.uk). For details of our 4 Year PhD programme, please see http://www.findaphd.com/search/PhDDetails.aspx?CAID=331&LID=2652
For a details of available projects click here http://www.ngcm.soton.ac.uk/projects/index.html