Neutrinos in non-linear structure formation — a simple SPH approach

TY - JOUR

T1 - Neutrinos in non-linear structure formation — a simple SPH approach

AU - Hannestad, Steen

AU - Haugbølle, Troels

AU - Schultz, Christian

PY - 2012/2

Y1 - 2012/2

N2 - We present a novel method for implementing massive neutrinos in N-body simulations. Instead of sampling the neutrino velocity distribution by individual point particles we take neutrino free-streaming into account by treating it as an effective redshift dependent sound speed in a perfect isothermal fluid, and assume a relation between the sound speed and velocity dispersion of the neutrinos. Although the method fails to accurately model the true neutrino power spectrum, it is able to calculate the total matter power spectrum to the same accuracy as more complex hybrid neutrino methods, except on very small scales. We also present an easy way to update the publicly available GADGET-2 version with this neutrino approximation.

AB - We present a novel method for implementing massive neutrinos in N-body simulations. Instead of sampling the neutrino velocity distribution by individual point particles we take neutrino free-streaming into account by treating it as an effective redshift dependent sound speed in a perfect isothermal fluid, and assume a relation between the sound speed and velocity dispersion of the neutrinos. Although the method fails to accurately model the true neutrino power spectrum, it is able to calculate the total matter power spectrum to the same accuracy as more complex hybrid neutrino methods, except on very small scales. We also present an easy way to update the publicly available GADGET-2 version with this neutrino approximation.

U2 - 10.1088/1475-7516/2012/02/045

DO - 10.1088/1475-7516/2012/02/045

M3 - Journal article

SN - 1475-7516

VL - 2

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

M1 - 045

ER -