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

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.