The halo model in a massive neutrino cosmology
  We provide a quantitative analysis of the halo model in the context of
massive neutrino cosmologies. We discuss all the ingredients necessary to model
the non-linear matter and cold dark matter power spectra and compare with the
results of N-body simulations that incorporate massive neutrinos. Our neutrino
halo model is able to capture the non-linear behavior of matter clustering with
a $\sim 20\%$ accuracy up to very non-linear scales of $k=10~h/$Mpc (which
would be affected by baryon physics). The largest discrepancies arise in the
range $k=0.5-1~h/$Mpc where the 1-halo and 2-halo terms are comparable and are
present also in a massless neutrino cosmology. However, at scales $k<0.2~h/$Mpc
our neutrino halo model agrees with the results of N-body simulations at the
level of 8\% for total neutrino masses of $<0.3$ eV. We also model the neutrino
non-linear density field as a sum of a linear and clustered component and
predict the neutrino power spectrum and the cold dark matter-neutrino
cross-power spectrum up to $k=1~h/$Mpc with $\sim$ 30\% accuracy. For masses
below 0.15 eV the neutrino halo model captures the neutrino induced
suppression, casted in terms of matter power ratios between massive and
massless scenarios, with a 2\% agreement with the results of N-body/neutrino
simulations. Finally, we provide a simple application of the halo model: the
computation of the clustering of galaxies, in massless and massive neutrinos
cosmologies, using a simple Halo Occupation Distribution scheme and our halo
model extension.
