2025/10/01 by Sauraj Bharti, Ashish Kumar Meena, Bharti, Sauraj +3
Physics and Astronomy · #Adaptive optics and wavefront sensing #Astronomy and Astrophysical Research #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Radio Astronomy Observations and Technology
paper · pdf · doi:10.48550/arxiv.2510.00813
openalex publication_date 2025/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The atomic hydrogen HI 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 HI gas over cosmic time has improved our understanding, direct HI 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 HI mass of galaxy populations. Gravitational lensing by the cluster lenses enhances the HI signal and can extend the redshift limit further. In this work, we describe simulations of HI lensing in cluster lenses. We explore the feasibility of detecting strongly lensed HI emission from background galaxies using known 50 cluster lenses within the uGMRT sky coverage. We demonstrate that certain clusters offer a strong likelihood of HI detection. We also investigate how strong lensing distorts the HI spectral lines. The shape of the HI signal in these lensing models provides useful information and can be used in optimising signal extraction in blind and targeted HI surveys. We find that blind detection of HI 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 HI emission in galaxies with strong optical lensing seems promising, with a 5σ detection potential in less than 50 hours for Abell 370 and 75 hours for Abell 1703 using the uGMRT.