Baryon-Dark matter interaction in presence of magnetic fields in light of EDGES signal

The Experiment to Detect the Global Epoch of reionization Signature (EDGES) collaboration has reported an excess absorption dip in the 21 cm signal during cosmic dawn era. The stronger than expected 21 absorption signal indicates that gas was much cooler than the standard cosmological prediction. The observed 21-cm signal can be explained by decreasing the gas temperature via baryon-DM interaction. In this work, we study the temperature evolution of the gas and Dark Matter (DM) in the presence of magnetic fields. The magnetic heating via ambipolar diffusion and the turbulent decay increases both the gas and DM temperature at low redshift and this heating is more in the favour of baryons compared to DM. In the presence of strong magnetic field, a large baryon-DM interaction cross section is required to balance magnetic heating to explain the EDGES signal as compared to weak magnetic field. We also study the brightness temperature during the cosmic dawn era and put constraint on the strength of the magnetic field for a particular mass and baryon-DM cross section.