  We present measurements of the specific angular momentum content (j) of
galaxies drawn from the Simba cosmological hydrodynamic simulations. For the
stellar, HI and baryonic matter components we demonstrate the existence of
extremely tight relations between j and the mass contained within the radius at
which the HI mass surface density decreases to 1 Msun/pc^2. These relations are
broadly consistent with a variety of empirical measurements. We confirm the
observational result that the scatter in the stellar j-M relation is driven
largely by HI content, and measure the dependence of its scatter on the
deviations of galaxies from other important scaling relations. For a given
stellar mass, HI-rich/poor galaxies have more/less-than-average stellar
specific angular momentum. A similar, yet weaker, correlation exists for HI
mass fraction. Overall, our results demonstrate the utility of the Simba
simulations as a platform for understanding and contextualising the data and
results from forthcoming large galaxy surveys.
