We update cosmological hot dark matter constraints on neutrinos and hadronic axions .
Our most restrictive limits use 7-year data from the Wilkinson Microwave Anisotropy Probe for the cosmic microwave background anisotropies , the halo power spectrum ( HPS ) from the 7th data release of the Sloan Digital Sky Survey , and the Hubble constant from Hubble Space Telescope observations .
We find 95 % CL upper limits of \sum m _ { \nu } < 0.44 eV ( no axions ) , m _ { a } < 0.91 eV ( assuming \sum m _ { \nu } = 0 ) , and \sum m _ { \nu } < 0.41 eV and m _ { a } < 0.72 eV for two hot dark matter components after marginalising over the respective other mass .
CMB data alone yield \sum m _ { \nu } < 1.19 eV ( no axions ) , while for axions the HPS is crucial for deriving m _ { a } constraints .
This difference can be traced to the fact that for a given hot dark matter fraction axions are much more massive than neutrinos .