  We investigate the relationship between the baryonic angular momentum and
mass for a sample of 36 isolated disc galaxies with resolved HI kinematics and
infrared WISE photometry drawn from -- and representative in terms of
morphologies, stellar masses and HI-to-star fraction of -- the
carefully-constructed AMIGA sample of isolated galaxies. Similarly to previous
studies performed on non-isolated galaxies, we find that the relation is well
described by a power law $j_{bar} \propto M_{bar}^\alpha$. We also find a slope
of $\alpha = 0.54 \pm 0.08$ for the AMIGA galaxies, in line with previous
studies in the literature; however, we find that the specific angular momenta
of the AMIGA galaxies are on average higher than those of non-isolated galaxies
in the literature. This is consistent with theories stipulating that
environmental processes involving galaxy-galaxy interaction are able to impact
the angular momentum content of galaxies. However, no correlation was found
between the angular momentum and the degree of isolation, suggesting that there
may exist a threshold local number density beyond which the effects of the
environment on the angular momentum become important.

Astrophysics of Galaxies