Instrumental Calibration for Observations of Redshifted 21-cm Signal from Neutral Hydrogen

Abstract

We investigate the calibration requirements for high dynamic range observations in radio interferometric experiments. Particularly, we access the requirement of the time-dependent instrumental gain calibration for observations of faint diffused emission in the presence of compact and bright diffused sources in the sky. This is particularly important for the observation of the redshifted 21-cm signal from the neutral hydrogen at different stages of the evolution of the universe. Our results suggests an order of magnitude better calibration compared to what is achieved at present is required to estimate the power spectrum of the redshifted 21-cm signal. © 2020 Indian Radio Science Society.