2025/03/26 by Alessandro Marins, Chang Feng, Marins, Alessandro +3 · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Radio Astronomy Observations and Technology #Superconducting and THz Device Technology
paper · pdf · doi:10.48550/arxiv.2503.20242
openalex publication_date 2025/03/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The neutral hydrogen (HI) signal is a crucial probe for astrophysics and cosmology, but it is quite challenging to measure from raw data because of bright foreground contaminants at radio wavelengths. Cross-correlating the radio observations with large-scale structure tracers (LSS) could detect faint cosmological signals since they are not correlated with the foreground, but exquisite component separation procedures must be performed to reduce the variance induced by the foreground. In this work, we adopt the lensing of the cosmic microwave background (CMB) as the LSS tracer and investigate the cross-correlation of CMB lensing and HI observations at the post-reionization epoch. We use simulations to study lensing and HI cross-correlations in the context of next-generation CMB and intensity mapping experiments. We investigate the impact of the component separation based on linear combinations of the HI observations at different frequencies and estimate the signal-to-noise ratios for the cross-correlation measurements in different scenarios.