Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Formation of Neutrino Stars from Cosmological Background Neutrinos   We study hydrodynamic evolution of cosmological background neutrinos. By
using a spherically symmetric Newtonian hydrodynamic code, we calculate the
time evolution of the density profiles of neutrino matter in cluster and
galactic scales. We discuss the possible observational consequences of such
evolution and the resulting density profiles of the degenerate neutrino `stars'
in galaxies and clusters.

35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph