Dark Matter Sterile Neutrino from Scalar Decays

We place constraints on DM sterile neutrino scalar decay production (SDP) assuming that sterile neutrinos representa fraction from the total Cold Dark Matter energy density. For the cosmological analysis we complement the CMB anisotropy measurements with CMB lensing gravitational potential measurements, that are sensitive to the DM distribution to high redshifts and with the cosmic shear data that constrain the gravitational potential at lower redshifts than CMB. We also use the most recent low-redshift BAO measurements that are insensitive to the non-linear effects, providing robust geometrical tests. We show that our datasets have enough sensitivity to constrain the sterile neutrino mass m(nu s) and the mass fraction f(S) inside the co-moving free-streaming horizon. We find that the best fit value m(nu s) = 7.88 +/- 0.73 keV (68% CL) is in the parameter space of interest for DM sterile neutrino decay interpretation of the 3.5 keV X-ray line and that f(S) = 0.86 +/- 0.07 (68% CL) is in agreement with the upper limit constraint on f(S) from the X-ray non-detection and Ly-alpha forest measurements that rejects f(S) = 1 at 3 sigma. However, we expect that the future BAO and weak lensing surveys, such as EUCLID, will provide much more robust constraints.

Automated summary

Constraints are placed on dark matter sterile neutrino scalar decay production, with results indicating that the mass fraction and mass of the sterile neutrino within the co-moving free-streaming horizon are constrained. The datasets used in the analysis provide sensitivity to these parameters and are in agreement with experimental observations.