Satellite galaxies as better tracers of the Milky Way halo mass [article]

Jiaxin Han, Wenting Wang, Zhaozhou Li
2019 arXiv   pre-print
The inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, phase correlations among tracer particles lead to an irreducible stochastic bias. This bias is small for satellite galaxies and dark matter particles, but as large as a factor of 2 for halo stars. This is consistent with the picture that satellite
more » ... closely trace the underlying phase space distribution of dark matter particles, while halo stars are less phase-mixed. As a result, the use of only ∼ 100 satellite galaxies can achieve a significantly higher accuracy than that achievable with a much larger sample of halo stars.
arXiv:1909.02690v1 fatcat:7ms3mncf4nd3tbeqdqyaesjtzu