Imprints of dark matter on 21 cm line in Cosmic Dawn Era

by Dr Alekha Nayak

Wednesday 16 Oct 2024, 16:30 → 17:10 Asia/Kolkata

About 27 % of the energy budget of the present Universe is composed of non-baryonic matter, also known as the dark matter (DM). The nature of dark matter is still unknown in modern physics. There have been several particle physics experiments going on to observe signal that are conclusively attributed to the dark matter particles. So far, the direct detection experiments such as LUX , XENON1T have yielded null results which constrain upper limits on the dark matter cross section with nucleons for DM mass range few GeV to TeV. Recently the Experiment to Detect the Global EoR Signature (EDGES) collaboration has reported an anomalous global 21 cm absorption signal during the Cosmic Dawn era which provides the nature of the interaction between baryons with sub-GeV dark matter. The 21 cm signal, due to the hyperfine transition between singlet and triplet states of the neutral hydrogen atom, appears to be a treasure trove to study physics in the cosmic dawn era. The presence of any exotic source of energy can inject energy into the intergalactic medium (IGM) and heat the gas. Subsequently, it can modify the absorption amplitude in the global 21-cm signal during cosmic dawn. We discuss how the 21 cm absorption signal during the cosmic dawn era shed light on the properties of dark matter.

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