Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constant surface gravity and density profile of dark matter   Cumulative observational evidence confirm that the surface gravity of dark
matter (DM) halo mu_{0 D} = r_0 rho_0 where r_0 and rho_0 are the halo core
radius and central density, respectively, is nearly constant and independent of
galaxy luminosity for a high number of galactic systems (spirals, dwarf
irregular and spheroidals, elliptics) spanning over 14 magnitudes in luminosity
and of different Hubble types. Remarkably, its numerical value mu_{0 D} = 140
M_{sun}/pc^2 = (18.6 Mev)^3 is approximately the same (up to a factor of two)
in all these systems. First, we present the physical consequences of the
independence of mu_{0 D} on r_0: the energy scales as the volume sim r_0^3
while the mass and the entropy scale as the surface ~ r_0^2 and the surface
times log r_0, respectively. Namely, the entropy scales similarly to the
black-hole entropy but with a much smaller coefficient. Second, we compute the
surface gravity and the density profile for small scales from first principles
and the evolution of primordial density fluctuations since the end of inflation
till today using the linearized Boltzmann-Vlasov equation. The density profile
rho_{lin}(r) obtained in this way decreases as r^{-1-n_s/2} for intermediate
scales where n_s = 0.964 is the primordial spectral index. This scaling is in
remarkable agreement with the empirical behaviour found observationally and in
N-body simulations: r^{-1.6\pm 0.4}. The observed value of mu_{0 D} indicates
that the DM particle mass m is in the keV scale. The theoretically derived
density profiles rho_{lin}(r) turn to be cored for m in the keV scale and they
look as cusped for m in the GeV scale or beyond. We consider both fermions and
bosons as DM particles decoupling either ultrarelativistically or
non-relativistically. Our results do not use any particle physics model and
vary slightly with the statistics of the DM particle.

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The categories of this paper are: stat
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
3
The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: econ
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The categories of this paper are: solv-int
30
The categories of this paper are: q-alg