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The dynamics of satellite and dark matter halo interactions on galaxy formation and evolution

Jun-Hwan Choi, University of Massachusetts Amherst


In my thesis, I research four consequences of satellite and dark matter halo interaction on galaxy formation. First, I investigate detailed physical processes in interaction between satellites and dark matter halos using analytic perturbation theory calculations and N-body simulations. The results suggest that resonant dynamics is a responsible physical mechanism for satellite-halo interaction. Comparison of different resolution simulations demonstrates that some resonances requires a larger number of halo particle to be reproduce and a low resolution simulation fails to do so. My results show two interesting physical processes in the satellite-dark matter halo interaction: significant dark matter halo central cusp excursion and effects of dark matter halo responses influence on a satellite decay rate. Second, I investigate detailed physical processes of satellite disruption in cold dark matter host halos using idealized N-body simulations. The simulation results show that the satellite heating by resonant interactions with its host halo is important. This resonant effect appears in two distinct types: resonant shock and resonant torque. Simulation results also show that the pattern of satellite stripping is outside-in process in energy space. Based on our simulation results, I suggest a new crude analytic estimation of satellite mass loss. Third, I study the evolution of satellite dark matter halos due to the interaction with cold dark matter subhalos by comparing simulations of the satellite evolution in halos with and without subhalos. According to my results, the satellites in the halo with subhalo lose more mass than the satellites in the smooth halo. The results also suggest that close encounter with subhalos is a more efficient way to satellite destruction. Satellite dark matter halo responses due to the interaction with the host halo and the subhalos produce a symmetric distortion. Fourth, I investigate the dynamical mechanisms responsible for producing tidal tails from dwarf satellites using N-body simulations. Using N-body simulations I identify two important dynamical co-conspirators: (1) the satellite deformation shows asymmetric distortion; (2) the satellite tail is continuously affected by satellite gravity. These two dynamical mechanisms significantly influence expected tidal tail morphology.

Subject Area


Recommended Citation

Choi, Jun-Hwan, "The dynamics of satellite and dark matter halo interactions on galaxy formation and evolution" (2007). Doctoral Dissertations Available from Proquest. AAI3289249.