Collisional Shaping of Nuclear Star Cluster Density Profiles. (arXiv:2310.19912v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Rose_S/0/1/0/all/0/1">Sanaea C. Rose</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacLeod_M/0/1/0/all/0/1">Morgan MacLeod</a>
A supermassive black hole (SMBH) surrounded by a dense, nuclear star cluster
resides at the center of many galaxies. In this dense environment,
high-velocity collisions frequently occur between stars. About $10 %$ of the
stars within the Milky Way’s nuclear star cluster collide with other stars
before evolving off the main-sequence. Collisions preferentially affect
tightly-bound stars, which orbit most quickly and pass through regions of the
highest stellar density. Over time, collisions therefore shape the bulk
properties of the nuclear star cluster. We examine the effect of collisions on
the cluster’s stellar density profile. We show that collisions produce a
turning point in the density profile which can be determined analytically.
Varying the initial density profile and collision model, we characterize the
evolution of the stellar density profile over $10$ Gyr. We find that old,
initially cuspy populations exhibit a break around $0.1$ pc in their density
profile, while shallow density profiles retain their initial shape outside of
$0.01$ pc. The initial density profile is always preserved outside of a few
tenths of parsec irrespective of initial conditions. Lastly, we comment on the
implications of collisions for the luminosity and color of stars in the
collisionly-shaped inner cluster.
A supermassive black hole (SMBH) surrounded by a dense, nuclear star cluster
resides at the center of many galaxies. In this dense environment,
high-velocity collisions frequently occur between stars. About $10 %$ of the
stars within the Milky Way’s nuclear star cluster collide with other stars
before evolving off the main-sequence. Collisions preferentially affect
tightly-bound stars, which orbit most quickly and pass through regions of the
highest stellar density. Over time, collisions therefore shape the bulk
properties of the nuclear star cluster. We examine the effect of collisions on
the cluster’s stellar density profile. We show that collisions produce a
turning point in the density profile which can be determined analytically.
Varying the initial density profile and collision model, we characterize the
evolution of the stellar density profile over $10$ Gyr. We find that old,
initially cuspy populations exhibit a break around $0.1$ pc in their density
profile, while shallow density profiles retain their initial shape outside of
$0.01$ pc. The initial density profile is always preserved outside of a few
tenths of parsec irrespective of initial conditions. Lastly, we comment on the
implications of collisions for the luminosity and color of stars in the
collisionly-shaped inner cluster.
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