Flattening of dark matter cusps during mergers: model of M31. (arXiv:2002.12192v2 [astro-ph.GA] UPDATED)

Flattening of dark matter cusps during mergers: model of M31. (arXiv:2002.12192v2 [astro-ph.GA] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Boldrini_P/0/1/0/all/0/1">Pierre Boldrini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mohayaee_R/0/1/0/all/0/1">Roya Mohayaee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Silk_J/0/1/0/all/0/1">Joseph Silk</a>

We run high resolution fully GPU N-body simulations to show that dark matter
distribution in M31 is well-fitted by a core-like profile. Rich observational
data especially on giant stellar stream provide stringent constraints on the
initial conditions of our simulations. We demonstrate that accretion of a
satellite on a highly eccentric orbit heats up the central parts of M31, causes
an outward migration of dark matter particles, flattens the central cusp over
more than a decade in scale and generates a new model-independent dark matter
profile that is well-fit by a core. Our results imply that core-like central
profiles could be a common feature of galaxies that have been initially cuspy
but have accreted satellites on eccentric orbits.

We run high resolution fully GPU N-body simulations to show that dark matter
distribution in M31 is well-fitted by a core-like profile. Rich observational
data especially on giant stellar stream provide stringent constraints on the
initial conditions of our simulations. We demonstrate that accretion of a
satellite on a highly eccentric orbit heats up the central parts of M31, causes
an outward migration of dark matter particles, flattens the central cusp over
more than a decade in scale and generates a new model-independent dark matter
profile that is well-fit by a core. Our results imply that core-like central
profiles could be a common feature of galaxies that have been initially cuspy
but have accreted satellites on eccentric orbits.

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