Astronomy & Space Sciences
Title : | Developing calibration algorithm for HI intensity mapping with the Square Kilometer Array |
Area of research : | Astronomy & Space Sciences |
Focus area : | Astrophysics and Cosmology |
Principal Investigator : | Dr. Prasun Dutta, Indian Institute Of Technology (Bhu), Uttar Pradesh |
Timeline Start Year : | 2024 |
Timeline End Year : | 2027 |
Contact info : | pdutta.phy@itbhu.ac.in |
Details
Executive Summary : | A major dark area in the present understanding of the evolution of the universe is the formation of the first luminous objects, the ionization of the universe (reionization), and the subsequent evolution of the neutral hydrogen density to form the structures like galaxies and clusters of galaxies we see today. Many of these questions can be addressed by studying the evolution of the spatial fluctuations in the neutral hydrogen density and its evolution over cosmic time by means of intensity mapping using the next generation radio interferometers like the Square Kilometer Array Telescopes (SKA). Amongst the many challenges to detect the redshifted 21-cm hyperfine structure transition signal of neutral hydrogen from the reionization and post-reionization era are the existence of many orders of magnitude higher foreground signals and tiny errors in the high dynamic range interferometric calibration procedures. Recently, we have demonstrated that the combination of these two poses a much deeper challenge. We used simple analytical models to demonstrate that the bias and variance of the standard HI power spectrum estimators in the presence of residual gain errors from standard calibration techniques severely limit the sensitivity of telescopes like the SKA, to the extent that its advantages are subsided. These calculations have been published in a series of three papers and have resulted in a PhD thesis. In this project, we shall first investigate more realistic effects of the residual gain errors lifting some of the original assumptions, understand and arrange the causes of these effects, and plan for a better calibration algorithm as well as do necessary modifications in the estimators of two-point correlation. These efforts are not only useful but essential for detecting the redshifted 21-cm radiation to understand cosmic evolution with SKA. As India is a major part of the international Square Kilometer Array Telescope Consortium, this project will be done in collaboration with research groups working at different institutions and universities in India and abroad. |
Total Budget (INR): | 6,60,000 |
Organizations involved