A new life for sterile neutrinos: resolving inconsistencies using hot
  dark matter
  Within the standard LCDM model of cosmology, the recent Planck measurements
have shown discrepancies with other observations, e.g., measurements of the
current expansion rate H_0, the galaxy shear power spectrum and counts of
galaxy clusters. We show that if LCDM is extended by a hot dark matter
component, which could be interpreted as a sterile neutrino, the data sets can
be combined consistently. A combination of Planck data, WMAP-9 polarisation
data, measurements of the BAO scale, the HST measurement of H_0, Planck galaxy
cluster counts and galaxy shear data from the CFHTLens survey yields Delta
N_eff = 0.61 pm 0.30 and m_s^eff = (0.41 pm 0.13) eV at 1 sigma. The former is
driven mainly by the large H_0 of the HST measurement, while the latter is
driven by cluster data. CFHTLens galaxy shear data prefer Delta N_eff >0 and a
non-zero mass. Taken together, we find hints for the presence of a hot dark
matter component at 3 sigma. A sterile neutrino motivated by the reactor and
gallium anomalies appears rejected at even higher significance and an
accelerator anomaly sterile neutrino is found in tension at 2 sigma.
