http://arxiv.org/abs/1904.09998
Milky Way (MW) satellites reside within dark matter (DM) subhalos with a broad distribution of circular velocity profiles. This large diversity poses a serious test for the structure formation theory with relevant implications for the DM nature. For the Cold Dark Matter model, the diversity might be a signature of the combined effects of subhalo tidal disruption by the MW disk and strong supernova feedback. For models with a dwarf-scale cutoff in the power spectrum, the diversity is a consequence of the lower abundance of dwarf-scale halos. This diversity is most challenging for Self-Interacting Dark Matter (SIDM) models with cross sections $\sigma/m_\chi\gtrsim1~$cm$^2$g$^{-1}$ where subhalos have too low densities to explain the ultra-faint galaxies. For much larger cross sections, the diversity could be a signature of gravothermal collapse, which would favor velocity-dependent SIDM models with $\sigma/m_\chi>$10 cm$^2$g$^{-1}$ at the scale of MW satellites.
J. Zavala, M. Lovell, M. Vogelsberger, et. al.
Wed, 24 Apr 19
18/51
Comments: 10 pages, 3 figures, to be submitted to Physical Review D