http://arxiv.org/abs/1906.11848
The density profiles of dwarf galaxies are a highly varied set. If the dark matter is an Ultra-light particle such as axions, then simulations predict a distinctive and unique profile. If the axion mass is large enough to fit the ultra-faint dwarf (UFD) satellites($m\gtrapprox 10^{-21}$ eV), then the models do not fit the density profile of Fornax and Sculptor and are ruled out by more than $3-\sigma$ confidence. If the axion mass is in the mass range that can fit mass profiles of Fornax and Sculptor dwarf spheroidals, then its extended profile implies enormous masses ($\approx10^{11}-10^{12}M_{\odot}$) for the UFDs. These large masses for the UFDS are ruled out by more than $3-\sigma$ confidence by dynamical friction arguments. The tension would increase further considering star formation histories and stellar masses of the UFDs. Moreover, light mass axions are inconsistent with the sub-halo mass function in the Milky Way.
M. Safarzadeh and D. Spergel
Mon, 1 Jul 19
22/52
Comments: submitted to ApJ Letters