Thursday, January 14, 3:30 p.m.
2015 McPherson Laboratory

Tidal evolution of Milky Way satellites

Ewa Lokas
Nicolaus Copernicus Astronomical Center

I will describe the properties and evolution of a population of subhaloes identified in a constrained simulation of a Local Group. I will discuss a few mechanisms that can contribute to the transformation of dwarf galaxies with disks into dwarf spheroidal galaxies that dominate among Milky Way satellites today: tidal stripping, mergers and infall in groups. It will be argued that the dominant mechanism is the tidal stirring since mergers are rare and membership in groups has little effect. The second part of the talk will be devoted to the analysis of the results of simulations dedicated to study the tidal effects in detail. I will discuss the mass loss, the morphological transformation and the transition from the streaming to random motion of the stars. The tidally induced effects that affect the mass modelling of dwarfs will also be addressed. I will show how the kinematic samples of dwarf galaxies can be contaminated by unbound stars from the tidal tails and how this and the non-sphericity of the stellar component may affect mass estimates.