Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galactic Halo Cusp versus Core: Tidal Effects in Mergers   We show how the buildup of halos by merging satellites forces an inner cusp,
with a density profile \rho \propto r^{-\alpha} where \alpha \to \alpha_a \gsim
1$. Our analysis is based on a new prescription for tidal stripping as a
function of \alpha(r), using a simple toy model which matches N-body
simulations. In a core of \alpha < 1 there is tidal compression rather than
stripping and the satellites sink towards the halo center, causing a rapid
steepening of the profile to \alpha > 1. Where \alpha > 1, the stripping of
each satellite shell is preceded by gradual puffing up, which makes the
stripping more efficient at larger \alpha, causing flattening where \alpha is
large enough. Therefore, we can show using linear perturbation analysis that a
sequence of mergers slowly leads to a fixed point \alpha(r)=\alpha_a. This
result implies that a cusp is enforced as long as enough satellite material
makes it into the inner halo and is deposited there. We conclude that in order
to maintain a flat core, as indicated by observations, satellites must be
disrupted outside the core, e.g., because of puffing up due to baryonic
feedback effects.

21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an