Mr. Prakash Gaikwad

The absorption features in the spectra of distant quasar by intergalactic neutral hydrogen is one of the most sensitive observations that put strong constraints on the end stages of reionization. The main challenge lies in observing the high redshift quasar and modeling the patchy reionization in cosmological simulations. In this talk, we present the measurement of the photo-ionization rate ($\Gamma_{\rm HI}$), the mean free path ($\lambda_{\rm mfp,HI}$) and the neutral fraction ($f_{\rm HI}$) of hydrogen at redshift $4.855$ suggesting the robustness and accuracy of the measured parameters. Finally we will discuss the implication of these measurements to our current cycle-2 JWST proposal and to future E-ELT / TMT observations.