My project aims at studying the transitioning HI-H 2 clouds in the early universe. We do this by looking at absorption lines created in the background
quasar light in a specific line of sight. High column density atomic gas leads
to saturation of the QSO light at specific wavelengths (like Lyman-alpha, beta,
etc.) creating a damped Voigt profile and hence, a specific class of these systems called the Extremely Strong Damped Lyman-Alpha Absorbers (ESD-
LAs) are tracers of very high-column density neutral gas. ESDLAs are found, in the past (in observations and simulations) to be located closer to their host galaxy. Hence, probing ESDLAs with the highest HI column density, we are likely to detect HI-H 2 transitioning gas in the interstellar medium/molecular clouds (ISM/MC), in absorption at Lyman-Werner bands
and possibly star-forming region, (in Lyman-alpha emission, optical emission lines), at high redshift, in a way which is not selected based on the strength
of the emission, and hence represents the general star-forming population at high redshifts. Using X-Shooter, we have observed a set of 11 ESDLAs selected based on high HI column density, which was predicted to
contain molecular hydrogen. We would like to emphasize results of very interesting ESDLA spectra (along the QSO line of sight, SDSS J1513+1352), which
also has an active star-forming signature. Along with this, I would also present
some brief statistical results which we have obtained by analysing the sample.