Stellar Profile Independent Determination of the Dark Matter Distribution of the Fornax Local Group Dwarf Spheroidal Galaxy. (arXiv:1912.01634v1 [astro-ph.GA])

Stellar Profile Independent Determination of the Dark Matter Distribution of the Fornax Local Group Dwarf Spheroidal Galaxy. (arXiv:1912.01634v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Brownsberger_S/0/1/0/all/0/1">Sasha Brownsberger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Randall_L/0/1/0/all/0/1">Lisa Randall</a>

The local group dwarf spheroidal galaxies (LG dSphs) are among the most
promising astrophysical targets for probing the small scale structure of dark
matter (DM) subhalos. We describe a method for testing the correspondence
between proposed DM halo models and observations of stellar populations within
LG dSphs. By leveraging the gravitational potential of any proposed DM model
and the available stellar kinematical data, we can derive a prediction for the
observed stellar surface density of an LG dSph that can be directly compared
with observations. Because we do not make any reference to an assumed surface
brightness profile, our model can be applied to exotic DM distributions that
produce atypical stellar density distributions. We use our methodology to
determine that the DM halo of the Fornax LG dSph is more likely cored than
cusped, ascertain that it is characterized by a semi-minor to semi-major axis
ratio in minor tension with simulations, and find no substantial evidence of a
disk within the dSph’s larger DM halo.

The local group dwarf spheroidal galaxies (LG dSphs) are among the most
promising astrophysical targets for probing the small scale structure of dark
matter (DM) subhalos. We describe a method for testing the correspondence
between proposed DM halo models and observations of stellar populations within
LG dSphs. By leveraging the gravitational potential of any proposed DM model
and the available stellar kinematical data, we can derive a prediction for the
observed stellar surface density of an LG dSph that can be directly compared
with observations. Because we do not make any reference to an assumed surface
brightness profile, our model can be applied to exotic DM distributions that
produce atypical stellar density distributions. We use our methodology to
determine that the DM halo of the Fornax LG dSph is more likely cored than
cusped, ascertain that it is characterized by a semi-minor to semi-major axis
ratio in minor tension with simulations, and find no substantial evidence of a
disk within the dSph’s larger DM halo.

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