http://arxiv.org/abs/1903.10712
Presently, the constraints on the scalar neutrino DM resonant production (RP) and scalar decay production (SDP) mechanisms are based on the power suppression of the gravitational clustering at small scales, dominated by non-linear effects. These constraints are in general obtained in the linear theory under the assumption that sterile neutrinos are all of the DM. In this paper, we analysed the validity of those scenarios through their impact on the acoustic scales, the small scale fluctuations and the low-redshift geometric observables, probes that are prevented from non-linear effects, relaxing the assumption of sterile neutrino DM as being all DM. We complement the reconstructed CMB gravitational lensing potential, that is sensitive to the DM distribution in the universe out to high redshifts with the cosmic shear data that constraints 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. Significantly, in the RP case we find that the best fit values of sterile neutrino DM mass and mixing angle are in the parameter space of interest for sterile neutrino DM decay interpretation of the 3.5 keV X-ray line with a DM mass fraction that excludes the assumption of sterile neutrinos as being all of the DM. In contrast, we find that SDP as a dominant DM mechanism. Sterile neutrino mass predicted by both RP and SDP are consistent within 0.3$\sigma$. We obtain cosmological constrains that clearly show that the present-day cosmological data does not exclude the existence of sterile neutrino DM, starting to discriminate between different sterile neutrino DM production mechanisms.
L. Popa
Wed, 27 Mar 19
8/74
Comments: 22 pages, 12 figures