The influence of angular momentum and environment on the H i gas of late-type galaxies

Abstract

We use high-resolution H I data from the Westerbork H I Survey of Spiral and Irregular Galaxies (WHISP) to study the H I and angular momentum properties of a sample of 114 latetype galaxies. We explore the specific baryonic angular momentuma-baryonic mass (jba-Mb)relation, and find that an unbroken power law of the form jb∝ M0.55±0.02bfits the data well, with an intrinsic scatter of ∼0.13 ± 0.01 dex. We revisit the relation between the atomic gas fraction, fatm, and the integrated atomic stability parameter q (the fatma-q relation), originally introduced by Obreschkow et al., and probe this parameter space by populating it with galaxies from different environments, in order to study the influence of the environment on their jb, fatm, and q values. We find evidence that galaxies with close neighbours show a larger intrinsic scatter about the fatma-q relation compared to galaxies without close neighbours. We also find enhanced star formation rate among the deviating galaxies with close neighbours. In addition, we use the bulge-to-total (B/T) ratio as a morphology proxy, and find a general trend of decreasing B/T values with increasing disc stability and H I fraction in the fatma-q plane, indicating a fundamental link between mass, specific angular momentum, gas fraction, and morphology of galaxies.