15.07.10 17:15

Local Group galaxies as critical tests of the contemporary cosmological model and its failure

P. Kroupa (Bonn)

Contemporary cosmology assumes the validity of the General Theory of Relativity which means that Newtonian dynamics is valid on the scales of galaxies. But this comes at a price: in order to account for the observed motions of stars and gas in and around galaxies the existence of exotic dark matter must be postulated. The resulting very popular concordance cosmological model then allows precise calculations of the matter distribution within and in the surroundings of galaxies. A very large volume of work has accumulated to date in an attempt to account for the existence and properties of galaxies such as our Milky Way, which must have evolved through a complex history of hierarchical structure growth driven by dark matter.The existing galaxies in the Local Group are compared to these theoretical results finding very significant disagreement in their overall properties. Furthermore, the concordance cosmological model implies that new dwarf galaxies be born during galaxy encounters. While this important process is usually ignored by the cosmological community, it appears to lead to a serious disagreement with the observed number of dwarf galaxies. Nearby as well as distant galaxies indeed look as if they were purely the result of baryonic processes.The observed phase-space distribution and the internal properties of the Milky Way satellite galaxies as well as the impressive similarity of large star-forming galaxies appear to lead, in view of the theoretical results, to the inescapable implication that the concordance cosmological model needs to be abandoned in favour of a model which relies mostly on baryon-driven processes, and thus to dynamics on galaxy scales being non-Newtonian.


(Seminarraum I)

Kategorie: Kolloquium