Exploring cosmological constraints of the weak gravitational lensing and galaxy clustering joint analysis in the CSST photometric survey

TL;DR

This study assesses the potential of the CSST photometric survey to constrain cosmological parameters through joint weak lensing and galaxy clustering analysis, using simulations and advanced statistical methods.

Contribution

It introduces a comprehensive simulation-based framework for analyzing CSST data, incorporating non-Gaussian covariance and systematics, to forecast cosmological constraints.

Findings

Constraints are comparable to Stage III surveys.

Full CSST survey can significantly improve constraints.

Survey demonstrates strong potential for cosmological exploration.

Abstract

We explore the joint weak lensing and galaxy clustering analysis from the photometric survey operated by the China Space Station Telescope (CSST), and study the strength of the cosmological constraints. We employ a high-resolution JiuTian-1G simulation to construct a partial-sky light cone to $z=3$ covering 100 deg$^2$, and obtain the CSST galaxy mock samples based on an improved semi-analytical model. We perform a multi-lens-plane algorithm to generate corresponding synthetic weak lensing maps and catalogs. Then we generate the mock data based on these catalogs considering the instrumental and observational effects of the CSST, and use the Markov Chain Monte Carlo (MCMC) method to perform the constraints. The covariance matrix includes non-Gaussian contributions and super-sample covariance terms, and the systematics from intrinsic alignments, galaxy bias, photometric redshift uncertainties, shear calibration, and non-linear effects are considered in the analysis. We find that the constraint result is comparable to that from Stage III surveys, and it can be significantly improved further in the full CSST survey with 17500 deg$^2$. This indicates the CSST photometric survey is powerful for exploring the Universe.