Abstract: Recently, to explain the origin of neutrino masses a model
based on confining some hidden fermionic bound states into right-handed
chiral neutrinos has been proposed. One of the consequences of condensing
the hidden sector fields in this model is the presence of sterile
composite Dirac neutrinos of keV mass, which can form viable warm dark
matter particles. We have analyzed constraints on this model from the
observations of satellite based telescopes to detect the sterile neutrinos
in clusters of galaxies.