Abstract
Neutral atomic hydrogen (HI) acts as the primary fuel reservoir for the star-formation process in galaxies. The HI mass function describes the distribution of the atomic hydrogen content of galaxies at a given epoch, and its evolution provides an important probe of models of galaxy formation and evolution. Unfortunately, the weakness of the HI 21cm line, the only probe of the HI mass of galaxies, has restricted our knowledge of the HI mass function to the nearby Universe. The evolution of the HI mass function with redshift has remained unclear due to the lack of observational constraints on the HI mass function at earlier epochs. In this talk I will discuss an indirect method of measuring the HI mass function using the measurements of HI scaling relations and luminosity functions. This method has led to the first measurement of the HI mass function beyond the local universe, at redshift z ~ 0.35, using data from a deep upgraded Giant Metrewave Radio Telescope HI 21 cm survey. I will also discuss how these measurements help us understand the evolution of the HI mass function and the neutral gas reservoir of galaxies over the past four billion years.
Biography
Dr. Apurba Bera is an expert on the evolution of galaxies and astrophysical fast transients. He obtained his BSc and MSc in Physics at Indian Institute of Technology in 2015, and then PhD from the National Centre for Radio Astrophysics, Tata Institute of Fundamental Research in 2021. After completing the PhD, he spent a year at Inter-University Centre for Astronomy and Astrophysics in India as a post-doctoral fellow, and then moved to International Centre for Radio Astronomy Research (ICRAR), Curtin University in Australia. He is currently a part of the CRAFT team, and working on Fast Radio Bursts using the ASKAP radio telescope.
Anyone interested is welcome to attend.