Too Big To Fail in Light of Gaia. (arXiv:1904.04939v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kaplinghat_M/0/1/0/all/0/1">Manoj Kaplinghat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valli_M/0/1/0/all/0/1">Mauro Valli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yu_H/0/1/0/all/0/1">Hai-Bo Yu</a>
We point out an anti-correlation between the central dark matter (DM)
densities of the bright Milky Way dwarf spheroidal galaxies (dSphs) and their
orbital pericenter distances inferred from Gaia data. The dSphs that have not
come close to the Milky Way center (like Fornax, Carina and Sextans) are less
dense in DM than those that have come closer (like Draco and Ursa Minor). The
same anti-correlation cannot be inferred for the ultra-faint dSphs due to large
scatter. Including ultra-faints, a trend that dSphs with more extended stellar
distributions tend to have lower DM densities emerges. A fresh look at
solutions to the too-big-to-fail problem is warranted in light of these
observations.
We point out an anti-correlation between the central dark matter (DM)
densities of the bright Milky Way dwarf spheroidal galaxies (dSphs) and their
orbital pericenter distances inferred from Gaia data. The dSphs that have not
come close to the Milky Way center (like Fornax, Carina and Sextans) are less
dense in DM than those that have come closer (like Draco and Ursa Minor). The
same anti-correlation cannot be inferred for the ultra-faint dSphs due to large
scatter. Including ultra-faints, a trend that dSphs with more extended stellar
distributions tend to have lower DM densities emerges. A fresh look at
solutions to the too-big-to-fail problem is warranted in light of these
observations.
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