Name: Ankita Bera
Affiliation: Presidency University
Conference ID : ASI2022_621
Title : Impact of cosmic ray heating on global 21-cm signal during cosmic dawn
Authors : Ankita Bera, Saumyadip Samui, Kanan K. Datta
Abstract Type: Poster*
Abstract Category : General Relativity and Cosmology
Abstract : The global HI 21-cm signal is an excellent tool for probing the thermal state of the IGM during the cosmic dawn. It is important to understand the processes through which the thermal state of the IGM evolved in the early universe. It is generally considered that the X-rays from the first accreting black holes or high mass X-rays binaries could heat the IGM during the cosmic dawn. We argue that the cosmic ray (CR) protons could also potentially heat the inter-galactic medium during the same epoch. We consider the CR protons generated from both early Pop III and Pop II stars. We then model the emission of cosmic ray particles from the first generation of sources. We also account for the physical processes by which cosmic rays can heat the IGM, and the feedback effects on their sources from the Lyman-Werner background. We find that the contribution of cosmic ray protons could be considered as a potential source of heating during cosmic dawn. It is interesting to note that it could explain the heating profile found in the EDGES absorption signal. Future 21-cm observations such as the Square Kilometre Array (SKA) could shed light on the contribution of cosmic rays heating and their sources.