http://arxiv.org/abs/1711.03502
Using the dataset of stellar kinematics for the brightest Milky Way dwarf spheroidal galaxies, we underpin the goodness of the self-interacting dark matter (SIDM) proposal as a solution to the “too-big-to-fail” problem through a detailed fit of the stellar velocity dispersion profiles. The kinematic data are consistent with SIDM if we allow for spatially varying stellar orbital anisotropies. We provide the first data-driven estimate for the SIDM cross-section per unit mass probed by these galaxies, pointing to $\sigma/m \sim$ 0.5 – 3 cm$^{2}$g$^{-1}$, in good agreement with recent estimates from the study of the dynamics in spiral galaxies. Our results well match the trends previously observed in pure SIDM N-body simulations. The analysis in this work outlines a complementary approach to simulations in testing SIDM with astrophysical observations.
M. Valli and H. Yu
Fri, 10 Nov 17
19/55
Comments: 6 pages, 3 figures, 1 table
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