📝 SummarXiv

Abstract

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 is essentially limited to $z \lesssim 0.42$ due to the faintness of the 21cm line. Detections beyond this redshift have made use of the stacking technique to obtain average quantities 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 line profile. 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. Detection of HI emission in galaxies where strong lensing has been observed in the optical appears to be more promising with potential for a $5\sigma$ detection in $<50$ hours of on-source observations for Abell 370 and in $<75$ hours for Abell 1703 with the uGMRT.