Cosmology from Cross- Correlations: CMB & Galaxy Surveys

Speaker: Neha Anil Kumar (Johns Hopkins University) zoom 

Zoom info: https://stanford.zoom.us/my/sihanyuan?pwd=QnpsUHZWWGJ2ekVYWmZVL3BmM0gzZ…

With increasingly precise data streams on the horizon—including impressively accurate measurements of the CMB signal and extensive surveys mapping millions of galaxies—cross-correlation science will become an invaluable tool in our quest to better understand the evolution of the Universe. In this talk, I will discuss several proposed cross-correlations between upcoming CMB datasets and galaxy surveys, focusing on their potential to improve measurements of two vastly separated epochs.

Given recent measurements of the kinetic Sunyaev-Zeldovich (kSZ) effect and its role in large-scale cosmological velocity reconstruction, I will first explore forecasts for constraining primordial non-Gaussianity of the local type (beyond fNL) using cross-correlations of the kSZ effect with upcoming galaxy-survey data. In the second part of my talk, I will present a case for using the same datasets to probe an epoch much closer to the present day — the epoch of helium reionization. I will talk about two different projects that focus on leveraging existing statistics, originally derived to probe hydrogen reionization using secondary effects imprinted in the observed CMB signal. I will discuss their applicability to the epoch of helium reionization and forecast how upcoming galaxy surveys will enhance our ability to characterize its patchy morphology through cross-correlations.