# The kinematic Sunyaev-Zel'dovich effect of the large-scale structure (I): dependence on neutrino mass

## TL;DR

This paper uses hydrodynamical simulations to analyze how the kinematic Sunyaev-Zel'dovich effect depends on neutrino mass and reionization redshift, providing insights into neutrino properties and large-scale structure.

## Contribution

The study introduces detailed simulations including neutrino mass variations to model the kSZ effect and explores its dependence on neutrino mass and reionization redshift.

## Key findings

- Massive neutrinos damp the kSZ power spectrum significantly.
- The kSZ power scales with reionization redshift as z_re^0.26.
- The dependence on neutrino fraction is shallower than for thermal SZ.

## Abstract

The study of neutrinos in astrophysics requires the combination of different observational probes. The temperature anisotropies of the cosmic microwave background induced via the kinematic Sunyaev-Zel'dovich (kSZ) effect may provide interesting information since they are expected to receive significant contribution from high-redshift plasma. We present a set of cosmological hydrodynamical simulations that include a treatment of the neutrino component considering four different sum of neutrino masses: $\Sigma m_\nu=(0,0.15,0.3,0.6)$ eV. Using their outputs, we modelled the kSZ effect due to the large-scale structure after the reionization by producing mock maps, then computed the kSZ power spectrum and studied how it depends on $z_{\rm re}$ and $\Sigma m_\nu$. We also run a set of four simulations to study and correct possible systematics due to resolution, finite box size and astrophysics. With massless neutrinos we obtain $\mathcal{D}^{\rm kSZ}_{3000}=4.0$ $\mu {\rm K}^2$ ($z_{\rm re}$=8.8), enough to account for all of the kSZ signal of $\mathcal{D}^{\rm kSZ}_{3000}=(2.9\pm1.3)$ $\mu {\rm K}^2$ measured with the South Pole Telescope. This translates into an upper limit on the kSZ effect due to patchy reionization of $\mathcal{D}^{\rm kSZ,patchy}_{3000}<1.0$ $\mu {\rm K}^2$ (95 per cent confidence level). Massive neutrinos induce a damping of kSZ effect power of about 8, 12 and 40 per cent for $\Sigma m_\nu=(0.15,0.3,0.6)$ eV, respectively. We study the dependence of the kSZ signal with $z_{\rm re}$ and the neutrino mass fraction, $f_\nu$, and obtain $\mathcal{D}^{\rm kSZ}_{3000}\propto z_{\rm re}^{0.26}(1-f_\nu)^{14.3}$. Interestingly, the scaling with $f_\nu$ is significantly shallower with respect to the equivalent thermal SZ effect, and may be used to break the degeneracy with other cosmological parameters.