Mittwoch, 31. März 2010 - 15:15
Paul Surajit (IUCAA):
"Evolution of structure formation shocks and turbulence in the web-like filamentary universe"
Zusammenfassung. Merging shocks in massive structures like cluster of galaxies are the most energetic processes in our universe. Such events are associated with production of megapersec scale shocks and large scale turbulence. In order to study the merger shocks and the subsequent injection of turbulence and its evolution we performed a set of cosmological simulations of major mergers in galaxy clusters. We used hydrodynamical code Enzo, with a refinement criterion especially designed for refining turbulent flows in the vicinity of shocks. How the shocks are generated and turbulence is injected and thereafter its evolution trough the realistic filamentary environment is studied thoroughly in our work. Our result reveals a new time scale of turbulence decay. Turbulence at the cluster center is seen to sustain for several Gigayears (~ 4 Gyr), which is substantially longer than typically assumed in the turbulent re-acceleration models, invoked for explaining the statistics of observed radio halos. Lastly, we will try to connect our work with the results obtained from the observations of Abell 3376.