  Slow rotator galaxies are distinct amongst galaxy populations, with
simulations suggesting that a mix of minor and major mergers are responsible
for their formation. A promising path to resolve outstanding questions on the
type of merger responsible, is by investigating deep imaging of massive
galaxies for signs of potential merger remnants. We utilise deep imaging from
the Subaru-Hyper Suprime Cam Wide data to search for tidal features in massive
($\log_{10}(M_*/M_{\odot}) > 10$) early-type galaxies (ETGs) in the SAMI Galaxy
Survey. We perform a visual check for tidal features on images where the galaxy
has been subtracted using a Multi-Gauss Expansion (MGE) model. We find that
$31\pm 2$ percent of our sample show tidal features. When comparing galaxies
with and without features, we find that the distributions in stellar mass,
light-weighted mean stellar population age and H$\alpha$ equivalent width are
significantly different, whereas spin ($\lambda_{R_e}$), ellipticity and bulge
to total ratio have similar distributions. When splitting our sample in age, we
find that galaxies below the median age (10.8 Gyr) show a correlation between
the presence of shells and lower $\lambda_{R_e}$, as expected from simulations.
We also find these younger galaxies which are classified as having "strong"
shells have lower $\lambda_{R_e}$. However, simulations suggest that merger
features become undetectable within $\sim 2-4$ Gyr post-merger. This implies
that the relationship between tidal features and merger history disappears for
galaxies with older stellar ages, i.e. those that are more likely to have
merged long ago.
