How to add massive neutrinos to your $\Lambda$CDM simulation --
  extending cosmology rescaling algorithms
  Providing accurate predictions for the spatial distribution of matter and
luminous tracers in the presence of massive neutrinos is an important task,
given the imminent arrival of highly accurate large-scale structure
observations. In this work, we address this challenge by extending
cosmology-rescaling algorithms to massive neutrino cosmologies. In this way, a
$\Lambda$CDM simulation can be modified to provide nonlinear structure
formation predictions in the presence a hot component of arbitrary mass, and,
if desired, to include non-gravitational modifications to the clustering of
matter on large scales. We test the accuracy of the method by comparing its
predictions to a suite of simulations carried out explicitly including a
neutrino component in its evolution equations. We find that, for neutrino
masses in the range $M_\nu \in [0.06, 0.3] ~ \mathrm{eV}$ the matter power
spectrum is recovered to better than $1\%$ on all scales
$k<2~h~\mathrm{Mpc}^{-1}$. Similarly, the halo mass function is predicted at a
few percent level over the range $M_{\rm halo} \in [10^{12}, 10^{15}] ~ h^{-1}
~ \mathrm{M}_{\odot}$, and so do also the multipoles of the galaxy 2-point
correlation function in redshift space over $r \in [0.1, 200] ~ h^{-1} ~
\mathrm{Mpc}$. We provide parametric forms for the necessary transformations,
as a function of $\Omega_{\rm m}$ and $\Omega_{\nu}$ for various target
redshifts.
