  The radiative decay of sterile neutrinos with typical masses of 10 keV is
investigated in the presence of a strong magnetic field and degenerate plasma.
Full account is taken of the strongly modified photon dispersion relation
relative to vacuum. The limiting cases of relativistic and non-relativistic
plasma are analyzed. The decay rate in a strongly magnetized plasma as a
function of the electron number density is compared with the un-magnetized
case. We find that a strong magnetic field suppresses the catalyzing influence
of the plasma on the decay rate.
