A Direct Detection of Neutral Hydrogen Intensity Mapping on Mpc Scales at z ≈ 0.32 and z ≈ 0.44
5 affiliations
- 1McGill University
- 2The University of Manchester
- 3University of the Western Cape
- 4The University of Edinburgh
- 5South African Radio Observatory (SARAO)
Abstract
We report the detection of the cosmological power spectrum using the intensity mapping signal from 21 cm emission of neutral hydrogen (H I ), derived from interferometric observations with the L -band receivers of the MeerKAT radio telescope. Intensity mapping is a promising technique to map the three-dimensional matter distribution of the Universe at radio frequencies and probe the underlying cosmology. So far, detections have only been achieved through cross-correlations with galaxy surveys. Here we present independent measurements of the H I power spectrum at redshifts 0.32 and 0.44 with the foreground avoidance method. We utilize two distinct frameworks for mitigating systematics: a conservative baseline-flagging-based approach achieves detections at 3.2 σ and 3.5 σ , and a power-spectrum-based flagging method enhances the significance to 5.9 σ and 9.18 σ , respectively. The information contained in the power spectrum measurements allows us to probe the parameters of the H I mass function and H I halo model. These results are a significant step toward precision cosmology with H I intensity mapping using the new generation of radio telescopes.
Related
- Cosmology beyond standard sirens: cross-correlation of gravitational waves and neutral hydrogen intensity mapping
- Flux Density Calibration of Radio Bursts Detected in the Sidelobes of the Canadian Hydrogen Intensity Mapping Experiment
- Cosmology with HI Intensity Mapping
- Constraining the z ≈ 1 neutral hydrogen (HI) distribution
- meer21cm: an Analysis Pipeline and Comprehensive Toolkit for HI Intensity Mapping
BibTeX
@article{paul2026direct,
title = {{A Direct Detection of Neutral Hydrogen Intensity Mapping on Mpc Scales at z ≈ 0.32 and z ≈ 0.44}},
author = {Sourabh Paul and Zhaoting Chen and Mário G. Santos and Laura Wolz},
journal = {The Astrophysical Journal Letters},
year = {2026},
month = jul,
doi = {10.3847/2041-8213/ae808f},
url = {https://doi.org/10.3847/2041-8213/ae808f},
note = {CC BY},
}
RIS
TY - JOUR
TI - A Direct Detection of Neutral Hydrogen Intensity Mapping on Mpc Scales at z ≈ 0.32 and z ≈ 0.44
AU - Sourabh Paul
AU - Zhaoting Chen
AU - Mário G. Santos
AU - Laura Wolz
PY - 2026
DA - 2026/07/06
JO - The Astrophysical Journal Letters
DO - 10.3847/2041-8213/ae808f
UR - https://doi.org/10.3847/2041-8213/ae808f
AB - We report the detection of the cosmological power spectrum using the intensity mapping signal from 21 cm emission of neutral hydrogen (H I ), derived from interferometric observations with the L -band receivers of the MeerKAT radio telescope. Intensity mapping is a promising technique to map the three-dimensional matter distribution of the Universe at radio frequencies and probe the underlying cosmology. So far, detections have only been achieved through cross-correlations with galaxy surveys. Here we present independent measurements of the H I power spectrum at redshifts 0.32 and 0.44 with the foreground avoidance method. We utilize two distinct frameworks for mitigating systematics: a conservative baseline-flagging-based approach achieves detections at 3.2 σ and 3.5 σ , and a power-spectrum-based flagging method enhances the significance to 5.9 σ and 9.18 σ , respectively. The information contained in the power spectrum measurements allows us to probe the parameters of the H I mass function and H I halo model. These results are a significant step toward precision cosmology with H I intensity mapping using the new generation of radio telescopes.
SN - 2041-8205
SN - 2041-8213
ER -