Cross-Correlation Forecast of CSST Spectroscopic Galaxy and MeerKAT Neutral Hydrogen Intensity Mapping Surveys

TL;DR

This study demonstrates that cross-correlating MeerKAT HI intensity mapping with CSST galaxy surveys significantly improves constraints on cosmic HI properties and galaxy evolution, surpassing current measurement precision.

Contribution

The paper introduces a simulation-based analysis of MeerKAT-CSST cross-correlation, showing enhanced parameter constraints and addressing foreground removal challenges in HI intensity mapping.

Findings

Constraint accuracy of $ ightarrow ext{~1 ext{ extperthousand}}$ for $ m \Omega_{HI}b_{HI}r_{HI,g}$ with 300 deg$^2$ survey.

Accuracy improves to $<0.3 ext{ extperthousand}$ with a 5000 deg$^2$ survey area.

Cross-correlation effectively probes cosmic HI and galaxy evolution.

Abstract

Cross-correlating the data of neutral hydrogen (HI) 21cm intensity mapping with galaxy surveys is an effective method to extract astrophysical and cosmological information. In this work, we investigate the cross-correlation of MeerKAT single-dish mode HI intensity mapping and China Space Station Telescope (CSST) spectroscopic galaxy surveys. We simulate a survey area of $\sim 300$ $\mathrm{deg}^2$ of MeerKAT and CSST surveys at $z=0.5$ using Multi-Dark N-body simulation. The PCA algorithm is applied to remove the foregrounds of HI intensity mapping, and signal compensation is considered to solve the signal loss problem in the HI-galaxy cross power spectrum caused by the foreground removal process. We find that from CSST galaxy auto and MeerKAT-CSST cross power spectra, the constraint accuracy of the parameter product $\Omega_{\rm HI}b_{\rm HI}r_{{\rm HI},g}$ can reach to $\sim1\%$, which is about one order of magnitude higher than the current results. After performing the full MeerKAT HI intensity mapping survey with 5000 deg$^2$ survey area, the accuracy can be enhanced to $<0.3\%$. This implies that the MeerKAT-CSST cross-correlation can be a powerful tool to probe the cosmic HI property and the evolution of galaxies and the Universe.