  The detection of excess radio background detected by ARCADE 2 suggests the
presence of new physics as there exists no clear astrophysical solution. We
find that the radiative decay of a relic neutrino into a sterile neutrino,
assumed to be quasi-degenerate, provides a very good fit to ARCADE 2 data. The
solution also predicts a stronger 21 cm absorption global signal than the
predicted one from the $\Lambda$CDM model, with a contrast brightness
temperature. The solution obtained is in mild tension with a much stronger
signal claimed by the EDGES collaboration.
