Reconstructing Dwarf Galaxy Progenitors from Tidal Streams

I will show that it is possible to estimate the dark matter content and radial distribution of a progenitor dwarf galaxy, reconstructed from the tidal stream it created. I produced a tidal stream that is similar in size and orbit to the Orphan Stream, from an N-body simulation of a dwarf galaxy disrupting in a Milky Way potential. In this simulation, the dwarf galaxy is modeled using bodies representing both baryonic and dark matter, which are allowed to interact as they are integrated along the Milky Way potential. I then used MilkyWay@home, a 0.5 PetaFLOPS distributed supercomputer, to find the parameters for the dwarf galaxy progenitor and the time the satellite has been disrupting, given the baryonic portion of the simulated tidal stream, the orbit, and the Galactic potential. This test shows that the dwarf galaxy dark matter mass, baryonic mass, and radial profile can be reconstructed under ideal conditions. Future work will explore the effects of incomplete knowledge of the dwarf galaxy and Galactic models, and physical processes that are not in the simulations, such as disk-subhalo interaction and the evolution of the Galaxy.

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