Executive Summary : | This proposal aims to push the limit towards detecting the cosmological 21-cm signal using the next-generation radio telescopes. This 21-cm signal from the hyperfine transition of neutral hydrogen contains lots of astrophysical and cosmological information. Earlier, we have analyzed the Giant Metrewave Radio Telescope (GMRT) data and learned many lessons to work with low-frequency radio observations; in particular, we have detected the Galactic synchrotron emission from our Milky Way Galaxy. We have developed a novel estimator namely, the Tapered Gridded Estimator (TGE), for the statistical detection of the cosmological 21-cm signal from radio interferometric visibilities. Here, we plan to extend our ideas and develop new tools for this purpose. The two next-generation telescopes, the Hydrogen Epoch of Reionization Array (HERA) and the Square Kilometre Array (SKA), are expected to detect it for the very first time, and this will open up an entirely new observational window to probe the first stars and galaxies. We plan to develop an end-to-end simulation pipeline to validate our algorithms, also analyze the real data to unveil the evolution history of the Universe using 21-cm radiation. India will soon become a full member of the SKA organization, so it will be a propitious timing for us to contribute to the international community. |