An efficient implementation of massive neutrinos in non-linear structure formation simulations

By Y. Ali-Haimoud, Simeon Bird. 2012

142 citations recorded by the source corpus.

Massive neutrinos make up a fraction of the dark matter, but due to their large thermal velocities, cluster signicantly less than cold dark matter (CDM) on small scales. An accurate theoretical modelling of their eect during the non-linear regime of structure formation is required in order to properly analyse current and upcoming high-precision large-scale structure data, and constrain the neutrino mass. Taking advantage of the fact that massive neutrinos remain linearly clustered up to late times, this paper treats the linear growth of neutrino overdensities in a non-linear CDM background. The evolution of the CDM component is obtained via N-body computations. The smooth neutrino component is evaluated from that background by solving the Boltzmann equation linearised with respect to the neutrino overdensity. CDM and neutrinos are simultaneously evolved in time, consistently accounting for their mutual gravitational inuence. This method avoids the issue of shot-noise inherent to particle-based neutrino simulations, and, in contrast with standard Fourier-space methods, properly accounts for the non-linear potential wells in which the neutrinos evolve. Inside the most massive late-time clusters, where the escape velocity is larger than the neutrino thermal velocity, neutrinos can clump non-linearly, causing the method to formally break down. It is shown that this does not aect the total matter power spectrum, which can be very accurately computed on all relevant scales up to the present time.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/21920625ec7bb5024c36c922e9c51db69ce38d6e

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Citations in the corpus

gevolution: a cosmological N-body code based on General Relativity (2016, methodology): “This method can be improved to take into account the potentials of nonlinearly evolved DM [53], however, it remains difficult to account for the phase information in the neutrino perturbations.”
DEMNUni: the clustering of large-scale structures in the presence of massive neutrinos (2015, background): “5h/Mpc (PMGRID=4096 and Lbox = 2h −1 Gpc), and, as discussed also in [39], this corresponds to wavenumbers which are at least two orders of magnitude smaller than the zero-redshift free-streaming lengths for the neutrino masses considered in our runs.”
Cosmology with massive neutrinos I: towards a realistic modeling of the relation between matter, haloes and galaxies (2013, methodology): “We notice that as a sanity check, we have also studied the bias using a completely different method to implement the effect of massive neutrinos in N-body simulations [73], finding the same results as with our standard neutrino-particle implementation.”