Theoretical Physics Colloquium

Early Universe at Radio Wavelengths: From the Cosmic Dawn to the Epoch of Reionization

by Prof. Abhirup Datta (IIT Indore)

Tuesday, December 7, 2021 from to (Asia/Kolkata)
at Zoom
Description
Detection of the redshifted 21-cm signal of neutral hydrogen is a promising probe to study physical processes in the early Universe from the Cosmic Dawn (CD) to the Epoch of Reionization (EoR). This quest has been extremely hard at low radio frequencies due to severely bright foregrounds, earth’s atmospheric corruption, and man-made radio frequency interference (RFI). The faint cosmological signal is much weaker than the astrophysical foregrounds and can be obscured by the instrumental systematics. However, recent development in RF technology at these wavelengths and progress made by telescopes like the LOFAR, MWA, PAPER, etc that the quest for the faint cosmological signal from the infant universe seems feasible. I will give an overview of the lessons learned so far from these early experiments about the observing strategies, techniques to deal with the systematics and obtain upper limits on the cosmological signal. With these lessons learned the construction of the next-generation radio telescope SKA (Square Kilometre Array) is underway. In my talk, I will present an update on the status of the SKA project in context with the experiment on CD/EoR. The major goal of the CD/EoR project in the SKA is to detect the redshifted HI signal fluctuations in the power spectrum domain. I will present an overview of the current plans for the CD/EoR observations with the SKA. In addition, I will also include some status update on some of the global signal experiments which are also designed to detect the all-sky averaged signal from CD/EoR.