Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Physics of Galaxy Clustering I: A Model for Subhalo Populations   (Abridged) We present a semi-analytic model for Cold Dark Matter halo
substructure that can be used as a framework for studying galaxy formation and
an ingredient in halo models of galaxy clustering. We perform a comprehensive
comparison of the model to the results of a suite of high-resolution
cosmological simulations. The comparisons reveal that subhalo statistics, such
as velocity and mass functions, radial distributions, and the halo occupation
distributions, agree well over three orders of magnitude in host halo mass at
various redshifts. Both in the simulations and in our model, the radial
distributions of subhalos are significantly shallower than that of the dark
matter density. The abundance of subhalos in a host is set by competition
between destruction and new accretion. High mass halos and halos at high
redshift tend to host more subhalos because the subhalos have, on average, been
accreted more recently. Similarly, at fixed mass, halos that formed more
recently host more subhalos. Observed "fossil groups" may represent an extreme
tail of this correlation. We find a related correlation between host halo
concentration and subhalo abundance at fixed host mass, Nsat ~ c^-a, where a
changes with redshift and host-to-subhalo mass ratio. Lastly, we use our model
to populate host halos in one of our high-resolution cosmological simulations,
replacing the subhalos resolved in the simulation with subhalos computed
according to our model. We show that the resulting 2pt correlation function of
such a "hybrid" halo ensemble is indistinguishable from that measured directly
in the simulation. This supports one of the key tenets of the standard halo
model -- the assumption that the halo occupation distribution is statistically
independent of host halo environment.

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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: cs
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: math
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The categories of this paper are: cond-mat