HI as a Probe of the Large Scale Structure in the Post-Reionization Universe

by Kanan Datta (SU)

Friday 29 Jan 2010, 10:30 → 11:30 Europe/Stockholm

FA31

Recently there has been significant interest in studying cosmology using radio interferometric observations of HI in the post reionization era. Observations suggest that small amount of (~3%) neutral Hydrogen (HI) survive after reionization. We model the distribution of HI in the post-reionization universe. This model uses gravity only N-Body simulations and an ansatz to assign HI to dark matter haloes that is consistent with observational constraints and theoretical models. We then compute the power spectrum of fluctuations in HI. We find the significantly high bias for the HI distribution at small scales. We then discuss the prospects for detection with the current and upcoming experiments. We also discuss prospects for direct detection of rare peaks in the HI distribution. We show that direct detection should be possible with integration time that is comparable to, or even less than, the time required for a statistical detection. Specifically, it is possible to make a statistical detection of the HI distribution by measuring the visibility correlation, and, direct detection of rare peaks in the HI distribution in less than 1000 hours with current and upcoming instruments.