Abstract DWARF SPHEROIDAL GALAXIES: KINEMATICS OF STELLAR POPULATIONS AND MASS MODELLING WITH TIDES

Dwarf Spheroidal galaxies (dSphs) are the nearest and the most dark matter dom-inated galaxies in the Universe. In this thesis, we study their kinematics and dy-namics using Monte Carlo methods. First, we study the kinematics of stellar sub-populations in dwarf spheroidal galaxies and present a robust Monte Carlo based method for interpretation of the sub-population data in dSphs. We apply the mehod to new spectroscopic data for twenty six stars in the recently-discovered Canes Ve-natici I (CVn I) dSph, obtained with the GMOS-N spectroscope on the Gemini North telescope. We use these data to investigate the recent claim of the presence of two dynamically different stellar populations in this system (Ibata et al., 2006). While we find no evidence for kinematically distinct sub-populations in our sample, we also show that the available kinematic data sets in CVn I might be too small to draw robust conclusions about its sub-populations. Second, we introduce a Markov Chain Monte Carlo based method for studying the dynamics of dSphs. We perform a large number of N-body simulations of the Carina dSph, modelling it with differ-ent dark matter halo profiles in the presence of tidal interactions. We show that du