The Three Hundred Project: The evolution of galaxy cluster density profiles. (arXiv:1812.04009v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mostoghiu_R/0/1/0/all/0/1">Robert Mostoghiu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Knebe_A/0/1/0/all/0/1">Alexander Knebe</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cui_W/0/1/0/all/0/1">Weiguang Cui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pearce_F/0/1/0/all/0/1">Frazer R. Pearce</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yepes_G/0/1/0/all/0/1">Gustavo Yepes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Power_C/0/1/0/all/0/1">Chris Power</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dave_R/0/1/0/all/0/1">Romeel Dave</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arth_A/0/1/0/all/0/1">Alexander Arth</a>
Recent numerical studies of the dark matter density profiles of massive
galaxy clusters ($M_{rm halo} > 10^{15}$M$_{odot}$) show that their median
radial mass density profile remains unchanged up to $z > 1$, displaying a
highly self-similar evolution. We verify this by using the data set of the THE
THREE HUNDRED project, i.e. 324 cluster-sized haloes as found in full physics
hydrodynamical simulations. We track the progenitors of the mass-complete
sample of clusters at $z=0$, and find that their median shape is already in
place by $z=2.5$. However, selecting a dynamically relaxed subsample ($sim16$
per cent of the clusters), we observe a shift of the scale radius $r_s$ towards
larger values at earlier times. Classifying the whole sample by formation time,
this evolution is understood as a result of a two-phase halo mass accretion
process. Early-forming clusters — identified as relaxed today — have already
entered their slow accretion phase, hence their mass growth occurs mostly at
the outskirts. Late-forming clusters — which are still unrelaxed today — are
in their fast accretion phase, thus the central region of the clusters is still
growing. We conclude that the density profile of galaxy clusters shows a
profound self-similarity out to redshifts $zsim2.5$. This result holds for
both gas and total density profiles when including baryonic physics, as
reported here for two rather distinct sub-grid models.
Recent numerical studies of the dark matter density profiles of massive
galaxy clusters ($M_{rm halo} > 10^{15}$M$_{odot}$) show that their median
radial mass density profile remains unchanged up to $z > 1$, displaying a
highly self-similar evolution. We verify this by using the data set of the THE
THREE HUNDRED project, i.e. 324 cluster-sized haloes as found in full physics
hydrodynamical simulations. We track the progenitors of the mass-complete
sample of clusters at $z=0$, and find that their median shape is already in
place by $z=2.5$. However, selecting a dynamically relaxed subsample ($sim16$
per cent of the clusters), we observe a shift of the scale radius $r_s$ towards
larger values at earlier times. Classifying the whole sample by formation time,
this evolution is understood as a result of a two-phase halo mass accretion
process. Early-forming clusters — identified as relaxed today — have already
entered their slow accretion phase, hence their mass growth occurs mostly at
the outskirts. Late-forming clusters — which are still unrelaxed today — are
in their fast accretion phase, thus the central region of the clusters is still
growing. We conclude that the density profile of galaxy clusters shows a
profound self-similarity out to redshifts $zsim2.5$. This result holds for
both gas and total density profiles when including baryonic physics, as
reported here for two rather distinct sub-grid models.
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