State of the Universe

# Higher-order clustering statistics in the Intergalactic Medium using Lyman-α forest

## by Mr. Soumak Maitra (IUCAA, Pune)

Friday, January 15, 2021 from to (Asia/Kolkata)
 Description The Intergalactic Medium (IGM) is a reservoir of the majority of baryonic content of the Universe and is intimately connected with the evolution of cosmic structures and various astrophysical processes. The matter distribution in the IGM manifests itself observationally in the form of HI Lyman-$\alpha$ forest absorption in the spectra of distant QSOs. Clustering studies of Lyman-α forest has been essential in understanding the matter distribution as well as thermal and ionization state of the IGM. Considerable work has been done involving two-point clustering statistics (two-point correlation or power spectrum) of Lyman-α forest, but higher-order clustering statistics remain largely unexplored. While higher-order clustering statistics have been explored in the case of galaxy clustering, Lyman-α forest will be able to characterize the underlying matter distribution at small scales and high redshift. The speaker will discuss higher-order clustering statistics, specifically three-point correlation statistics of Lyman-α forest, and its dependence on various astrophysical parameters. The speaker will also talk about the recent detection of non-gaussianity in low-redshift (z<0.48) Lyman-α forest.