2022MNRAS.513.5310B

We investigate the effect of observational constraints such as signal-to-noise (S/N) ratio, resolution, and column density level on the H I morphological asymmetry (A_mod) and the effect of noise on the H I global profile (A_flux) asymmetry indices. Using mock galaxies from the EAGLE simulations, we find an optimal combination of the observational constraints that are required for a robust measurement of the A_mod value of a galaxy: a column density threshold of 5 x 10¹⁹ cm^–2 or lower at a minimal S/N of 3 and a galaxy resolved with atleast 11 beams. We also use mock galaxies to investigate the effect of noise on the A_flux values and conclude that a global profile with S/N greater than 6 is required to achieve a robust measurement of asymmetry. We investigate the relation between A_mod and A_flux indices and find them to be uncorrelated, which implies that A_flux values cannot be used to predict morphological asymmetries in galaxies.