Work

Gravitational lensing of 21 cm H i signal: detection prospects at z ∼ 1 with the uGMRT in galaxy cluster lenses

Year: 2025

Type: article

Abstract: ABSTRACT The atomic hydrogen H i content of galaxies is intimately related to star formation and galaxy evolution through the baryon cycle, which involves processes such as accretion, feedback, outflows, and gas recycling. While probing the H i gas over cosmic time has improved our understanding, direct H i detection with the redshifted 21 cm line is essentially limited to $z\lesssim 0.42$. Detections beyond this redshift are based on stacking to obtain average H i mass of galaxy populations. Gravitational lensing by the cluster lenses enhances the H i signal and can extend the redshift limit further. In this work, we describe simulations of H i lensing in cluster lenses. We explore the feasibility of detecting strongly lensed H i emission from background galaxies using known 50 cluster lenses within the upgraded Giant Metrewave Radio Telescope (uGMRT) sky coverage. We demonstrate that certain clusters offer a strong likelihood of H i detection. We also investigate how strong lensing distorts the H i spectral lines. The shape of the H i signal in these lensing models provides useful information and can be used in optimizing signal extraction in blind and targeted H i surveys. We find that blind detection of H i signal from galaxies in the redshift range up to 1.58 requires more than a few hundred hours of observations of individual clusters with the uGMRT. Detecting H i emission in galaxies with strong optical lensing seems promising, with a $5\sigma$ detection potential in less than 50 h for Abell 370 and 75 h for Abell 1703 using the uGMRT.

Source: Monthly Notices of the Royal Astronomical Society

DOI: 10.1093/mnras/staf2244

Authors: Sauraj Bharti, Ashish Kumar Meena, Jasjeet Singh Bagla

Institutions: Indian Institute of Science Education and Research Mohali, Ben-Gurion University of the Negev, Indian Institute of Science Bangalore, Tata Institute of Fundamental Research, National Centre for Radio Astrophysics

Language: English

Topic: Galaxies: Formation, Evolution, Phenomena

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $3,046

Funders: National Aeronautics and Space Administration, Space Telescope Science Institute, Department of Science and Technology, Ministry of Science and Technology, India