Application of cross correlations between CMB and large scale structure to constraints on the primordial non-Gaussianity

TL;DR

This paper enhances constraints on primordial non-Gaussianity by incorporating galaxy lensing shear and redshift slicing into cross-correlation analyses between CMB and large-scale structure, improving previous limits.

Contribution

It introduces the inclusion of galaxy lensing shear and redshift slicing in cross-correlation analysis to better constrain primordial non-Gaussianity.

Findings

Constraint on fNL improves from 5.4 to 5.1 with HSC data.

Further improves to 4.8 when including ACTPol and Planck data.

Redshift slicing enhances the sensitivity of the analysis.

Abstract

The primordial non-Gaussianity of local type affects the clustering of dark matter halos, and the planned deep and wide photometric surveys are suitable for examining this class of non-Gaussianity. In our previous paper, we investigated the constraint from the cross correlation between CMB lensing potential and galaxy angular distribution on the primordial non-Gaussianity, without taking into account redshift slicing. To improve our previous analysis, in this paper, we add the galaxy lensing shear into our analysis and take into account redshift slicing to follow the redshift evolution of the clustering. By calculating 81 power spectra and using the Fisher matrix method, we find that the constraint on the primordial non-Gaussianity can be improved from {\Delta}fNL \sim 5.4 to 5.1 by including the galaxy-galaxy lensing shear cross correlations expected from the Hyper Suprime-Cam survey (HSC), in comparison with the constraint without any cross correlations. Moreover, the constraint can go down to {\Delta}fNL \sim 4.8 by including the galaxy-CMB lensing cross correlations from the ACTPol and Planck experiments.