Exploring Joint Observation of the CSST Shear and clustering of astrophysical gravitational wave source measurements

TL;DR

Multi-messenger cosmology is enabled by combining CSST weak lensing with AGWS clustering from third-generation GW detectors to map large-scale structure and the expansion history. The authors develop a theoretical framework to compute auto- and cross-angular power spectra among AGWS clustering, CSST shear, and their cross-correlation, and generate realistic mocks including detector selection effects and lensing systematics. They constrain $\Lambda$CDM parameters, GW source bias, and cosmic star formation rate using MCMC across three GW networks, achieving sub-$5\%$ precision on $H_0$ and $w$ (e.g., $H_0$ to $2.19\%$, $w$ to $5.7\%$) and $\sim4$–$5\%$ precision on AGWS bias. The results show the joint approach can break degeneracies and provide independent validation for the $H_0$ tension, highlighting the potential of CSST–3G GW synergy for probing large-scale structure and the cosmic expansion history.

Abstract

We present a comprehensive forecast for cosmological constraints using the joint observation of the cosmic shear signal from the Chinese Space Station Survey Telescope (CSST) and the clustering signal from the next-generation gravitational wave (GW) detector networks, e.g. Einstein Telescope (ET) and Cosmic Explorer (CE). By leveraging the angular clustering of astrophysical gravitational wave sources (AGWS) from the third-generation detectors and CSST's weak lensing surveys, we develop a theoretical framework to compute auto- and cross-angular power spectra of AGWS clustering, cosmic shear, and their cross-correlation. Mock datasets are generated by considering the detector-specific selection functions, uncertainties in luminosity distance, and weak lensing systematics. We employ the Markov Chain Monte Carlo (MCMC) methods to constrain the $Λ\mathrm{CDM}$ cosmological parameters, AWGS bias parameters, and star formation rate (SFR) parameters under three detector configurations. Our results demonstrate that the joint observation can achieve sub-$5\%$ precision on $H_0$ ($2.19\%$) and $w$ ($5.7\%$). Besides, the AGWS clustering bias parameters can be constrained to the precision of $4\%-5\%$, enabling the differentiation between stellar-origin compact binaries and primordial black hole scenarios. This multi-messenger approach can also be helpful to resolve mass-redshift degeneracies in the dark siren methods, providing independent validation for the Hubble tension. Our work indicates that the joint observation of the third-generation GW detectors and the CSST can be a powerful probe of the large-scale structure and the cosmic expansion history.

Figures (17)

• Figure 1: The functions of $S_i(z)$ (left panel) and $T_i(z)$ (right panel), based on the ECS configuration of the GW detector network.
• Figure 2: The weighting functions of $W_i^S(z)$ (left panel) and $W_i^T(z)$ (right panel), based on the ECS configuration of the GW detector network.
• Figure 3: The weighting functions $W_i^G(z)$ (left panel) and $W_i^I(z)$ (right panel), based on the ECS configuration of the GW detector network.
• Figure 4: The ASD curves of the two generation GW detectors, including Advanced-plus upgrade of LIGO (A+: Hanford, Livingston, and India), Virgo (V+: Italy), and KAGRA (K+: Japan), and the third generation detectors Einstein Telescope (ET) and Cosmic Explorer (CE). The ET ASD is scaled by a factor of $2/3$ to represent the effective sensity of ET's triangular design, which is used in our analysis.
• Figure 5: Detection rate comparison for the three detector networks. For BBH and BNS systems, we employ three-parameter sigmoid function fits (as listed in Table \ref{['table_detec']}) to model their detection rates. For BHNS systems, we adopt the simplified assumption $E_{\rm det}^{\rm BHNS}(z)=1/2 \left[E_{\rm det}^{\rm BBH}(z)+E_{\rm det}^{\rm BNS}(z)\right]$.