IISER MOHALI

Abstract: The study of the Universe's large-scale structure and evolution has entered a new era with the emergence of neutral hydrogen (HI) intensity mapping as a powerful observational technique. HI intensity mapping (IM) offers a unique and innovative approach to cosmological research by probing the distribution of neutral hydrogen on vast scales. This technique uses radio telescopes like MeerKAT to detect the cumulative 21cm emission from neutral hydrogen. In this talk, I will introduce our current HI IM experiment with MeerKAT in the post-reionization universe and discuss our recent breakthroughs in the field. Additionally, I will present the on-the-fly (OTF) interferometric imaging capabilities with MeerKAT. Our aim is to explore cosmology through single-dish HI intensity mapping while simultaneously generating continuum images via the interferometer. This technique allows for commensal observing for both intensity mapping and interferometric imaging. We plan to survey an extensive 10,000 square degrees in the UHF band, achieving a sensitivity of 25 uJy/beam rms and a resolution of 13’’. Our partial observations have achieved an image sensitivity of approximately 140 uJy, with a goal of reaching 30 uJy using existing data. These advanced techniques are propelling the joint studies of cosmology and radio astronomy to new heights, and with the emergence of the Square Kilometre Array (SKA), the future of this field looks exceptionally promising.