Investigating cross-correlations between cosmic microwave background lensing and 21 cm intensity mapping

Fuente: arXiv
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Autori principali: Marins, Alessandro, Feng, Chang, Abdalla, Filipe B.
Natura: Preprint
Pubblicazione: 2025
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author Marins, Alessandro
Feng, Chang
Abdalla, Filipe B.
author_facet Marins, Alessandro
Feng, Chang
Abdalla, Filipe B.
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2503_20242
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Investigating cross-correlations between cosmic microwave background lensing and 21 cm intensity mapping
Marins, Alessandro
Feng, Chang
Abdalla, Filipe B.
Cosmology and Nongalactic Astrophysics
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.
title Investigating cross-correlations between cosmic microwave background lensing and 21 cm intensity mapping
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2503.20242