Seminar by Raphaël Errani, Carnegie Mellon
Guided by the recent discovery of the faint Milky Way satellite UMa 3/Unions I, in this talk I will present the results of our controlled high-resolution simulations to discuss how micro galaxies could be distinguished observationally from self-gravitating star clusters, and how such systems would help us to constrain both the properties of dark matter and the physical processes underlying the formation of the faintest of galaxies. Micro galaxies are a plausible prediction of Cold Dark Matter (CDM) cosmology: The centrally-divergent density cusps of CDM subhaloes render them remarkably resilient to tides. Heavily stripped tidal remnants of the Milky Way accretion may survive even in the strong tidal field of the inner regions of our Galaxy. Some of these tidal remnants may have been sufficiently massive in the past to allow for star formation within their potential wells, giving rise to a population of micro galaxies: co-moving groups of stars, gravitationally supported by the dark matter subhalo which surrounds them.
Host: Kathryn Johnston