Khandakar Md Asif Elahi

My research focuses on statistical measurements of the neutral hydrogen 21-cm signal from the early Universe. A successful measurement of this signal can reveal the history and evolution of the first stars and galaxies, the large-scale distribution of galaxies, and the nature of the mysterious components known as dark energy and dark matter. I pursue this goal using cutting-edge radio interferometers such as the GMRT, MWA, HERA, and SKA. These experiments require separating an extremely faint cosmological signal from foreground emission that is many orders of magnitude brighter, arising from our own Galaxy and from other galaxies. I develop component-separation techniques to make these measurements robust. During my PhD, I used the GMRT to place tight constraints on the signal from the post-reionization epoch. I then turned to the MWA in Australia, which targets the reionization history of the Universe, and have placed several constraints on the signal’s two- and three-point statistics. My current work aims to tighten these constraints with more observations and improved techniques, while laying the groundwork for 21-cm cosmology with the upcoming SKA Observatory.