Facundo A. Gómez, Ivan Minchev, Brian W. O'Shea, Young Sun Lee, Timothy C. Beers, Deokkeun An, James S. Bullock, Chris W. Purcell, Álvaro Villalobos
It is now known that minor mergers are capable of creating structure in the
phase-space distribution of their host galaxy's disc. In order to search for
such imprints in the Milky Way, we analyse the SEGUE G-dwarf and the Schuster
et al. (2006) stellar samples. We find similar features in these two completely
independent stellar samples, consistent with the predictions of a Milky Way
minor-merger event. We next apply the same analyses to high-resolution,
idealised N-body simulations of the interaction between the Sagittarius dwarf
galaxy and the Milky Way. The energy distributions of stellar samples in small
spatial regions in the host disc reveal strong variations of structure with
position. We find remarkable matches to the observations for models with a mass
of Sagittarius' dark matter halo progenitor $\lessapprox 10^{11}$ M$_{\odot}$.
Thus, we show that this kind of analysis could be used to provide
unprecedentedly tight constraints on Sagittarius' orbital parameters, as well
as place a lower limit on its mass.
View original:
http://arxiv.org/abs/1201.5898
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