| Description |
The large volume probed by the Lyman-Alpha (Ly ) forest makes it an ideal tool to perform cosmological and astrophysical analyses. Using the Ly forest data from BOSS DR12, I make the most precise estimate to date of the evolution of the mean transmission of the neutral hydrogen in the intergalactic medium. The parameters describing the redshift evolution are estimated with a precision of 2.2%. I utilize a novel technique to mitigate the e ects of systematic errors. This work can be extended to obtain constraints from higher-order statistics derived from Ly forest. Voids, which are under-dense regions of the Universe nearly devoid of galaxies, provide a unique environment to study galaxy formation and the e ects of dark energy. We estimate the underlying ux density eld from the Ly forest in the BOSS reverberation-mapping (RM) data using Wiener reconstruction. Using the concept of persistent homology, we characterize voids in the cosmological matter density eld in this reconstructed map. The multi-epoch observations available in RM survey will allow us to test the robustness of continuum- tting and ux calibration, which constitute the key uncertainties in Ly forest studies. The Python code for both of these projects is freely available to download on Github at https://github.com/VikrantKamble. |
