Daftar Isi: Resolving Atomic Hydrogen in Galaxies in Next-Generation Radio Surveys Using High-Resolution Optical-Near-infrared Imaging

Daftar Isi:

Multi-wavelength analyses of galaxies is a vital component of studying galaxy evolution. In the radio regime, the intrinsically weak flux of the neutral hydrogen (HI) signal often requires stacking of multiple sources; this has become commonplace for the statistical detection of HI line profiles in deep-fields from SKA precursor-surveys. In contrast, we are developing algorithms for 3D data-cube stacking to take advantage of wide-field surveys to study the resolved spatial distribution and kinematics of neutral hydrogen at moderate redshifts. Our aim is to develop a stacking algorithm based solely on optical and near-infrared (OIR) measurements. These OIR measurements are used to infer HI properties through a variety of well-known scaling relations, with the addition of shape parameters that better characterize both spatial and spectral distributions of HI emission. The algorithm makes use of these scalings to co-align galaxies’ flux distributions in 3D prior to stacking. We demonstrate our algorithm using WHISP 21-cm data-cubes and ground-based imaging of nearby galaxies. The algorithm will be applied to HI deep-fields with HST imaging (e.g., CHILES/COSMOS and LADUMA/GEMS). In basing the algorithm on measurements of galaxy parameters done in the OIR regime, we hope to utilise the high-SNR, high-resolution and widely-mapped regions of the sky made available by the Nancy Grace Roman Space Telescope.