Bounds on sterile neutrino lifetime and mixing angle with active neutrinos by global 21 cm signal

Abstract

Sterile neutrinos can be a possible candidate for dark matter. Sterile neutrinos are radiatively unstable and can inject photon energy into the intergalactic medium (IGM). The injection of photon energy into IGM can modify the temperature and ionization history of IGM gas during cosmic dawn. Theoretical models based on the ΛCDM framework predict an absorption profile in the 21 cm line during the cosmic dawn era. Recently, the Experiment to Detect the Global Epoch of Reionization Signature (EDGES) collaboration confirmed such an adsorption signal. Injection of energy into IGM can modify the absorption amplitude in the 21 cm signal. Considering the 21 cm absorption signal at cosmic dawn, we constrain the lifetime of sterile neutrinos and the mixing angle of sterile neutrinos with active neutrinos. We also compare these bounds with other astrophysical observational bounds.