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

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: Σmν = (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 zre and Σmν. 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 D^kSZ_{3000} = 4.0 μK2 (zre = 8.8), enough to account for all of the kSZ signal of D^kSZ_{3000} = (2.9 ± 1.3) μK2 measured with the South Pole Telescope. This translates into an upper limit on the kSZ effect due to patchy reionization of D^kSZ,patchy_{3000} < 1.0 μK2 (95 per cent confidence level). Massive neutrinos induce a damping of kSZ effect power of about 8, 12 and 40 per cent for Σmν = (0.15, 0.3, 0.6) eV, respectively. We study the dependence of the kSZ signal with zre and the neutrino mass fraction, fν, and obtain D^kSZ_{3000} ∝ zre0.26(1 - fν)14.3. Interestingly, the scaling with fν is significantly shallower with respect to the equivalent thermal SZ effect, and may be used to break the degeneracy with other cosmological parameters.