Exploring Cosmological Constraints of the Void-Lensing Cross-Correlation in the CSST Photometric Survey

TL;DR

This study demonstrates that void-lensing cross-correlation analysis in the CSST photometric survey can effectively constrain cosmological parameters, offering a valuable complement to traditional weak lensing methods especially at high redshift.

Contribution

The paper introduces a novel application of void-lensing cross-correlation in the CSST survey, modeling the cross-power spectrum with HVDM and employing MCMC for parameter constraints.

Findings

Void-lensing analysis yields constraints comparable or superior to weak lensing alone.

Method accurately extracts cosmological information from mock data.

Void-lensing serves as an effective and complementary cosmological probe.

Abstract

We investigate the cosmological constraints from the void-lensing cross-correlation assuming the $w$CDM model for the Chinese Space Station Survey Telescope (CSST) photometric survey. Using Jiutian simulations, we construct a mock galaxy catalog to $z=3$ covering 100 deg$^2$, which incorporates the instrumental and observational effects of the CSST. We divide the galaxy sample into seven photometric-redshift (photo-$z$) tomographic bins and identify 2D voids within each bin using the Voronoi tessellation and watershed algorithm. We measure the angular cross-power spectrum between the void distribution and the weak lensing signal, and estimate the covariance matrix via jackknife resampling combined with pseudo-$C_{\ell}$ approach to account for the partial sky correction. We employ the Halo Void Dust Model (HVDM) to model the void-matter cross-power spectrum and adopt the Markov Chain Monte Carlo (MCMC) technique to implement the constraints on the cosmological and void parameters. We find that our method can accurately extract the cosmological information, and the constraint accuracies of some cosmological parameters from the void-lensing analysis are comparable or even tighter than the weak lensing only case. This demonstrates that the void-lensing serves as an effective cosmological probe and a valuable complement to galaxy photometric surveys, particularly for the Stage-IV surveys targeting the high-redshift Universe.