Massive neutrinos in nonlinear large scale structure: A consistent perturbation theory

Understand

A consistent formulation to incorporate massive neutrinos in the perturbation theory of the effective CDM+baryons fluid is introduced.

• In this formulation all linear k dependence in the growth functions of CDM+baryons perturbations, as well as all consequent additional mode coupling at higher orders, are taken into account to any desirable accuracy.
• Our formulation regards the neutrino fraction, which is constant in time after the non-relativistic transition of neutrinos, and much smaller than unity, as the coupling constant of the theory.
• Then the "bare" perturbations are those in the massless neutrino case when the neutrino fraction vanishes, and we consider the backreaction corrections due to the gravitational coupling of neutrinos.