  Context: To study the effects of environment on galaxies we use HI
observations of galaxies in and around the cluster A2626. The cluster can
effectively be divided in three different environments: the cluster itself, a
group environment in the periphery of the cluster (we call it the Swarm) and
substructure in the cluster itself. We use these to study the dependence of
galaxy properties on environment. Aims: We have explored the relationship
between HI deficiency, HI morphology, and star formation deficiency for the
galaxies in and around the A2626 galaxy cluster to investigate the
environmental effects on those properties. Methods: To quantify asymmetries of
the outer HI disc of a galaxy, we used 1) three visual classes based on the
outermost reliable HI contour (settled, disturbed, unsettled HI discs), 2) the
offset between the HI centre and the optical centre of a galaxy, and 3) the
modified asymmetry parameter Amod as defined by Lelli et al. (2014). Results:
The HI deficiency of a galaxy is strongly correlated with the projected
distance from the centre of A2626. Furthermore, substructure galaxies tend to
be more asymmetric than the isolated galaxies in A2626, plausibly because of
more efficient tidal interactions within substructures than outside
substructures. Moreover, asymmetric, offset, and smaller HI discs are not
necessarily the result of the cluster environment, as they are also observed in
substructures in A2626 and in the Swarm. This signifies that "pre-processing"
of the HI discs of galaxies in groups or substructures plays an important role,
together with the "processing" in the cluster environment. Finally, the
galaxies in all three environments have slightly lower star-formation rates
(SFRs) than the typical SFR for normal galaxies as manifested by their offset
from the star formation main sequence, implying effective gas removal
mechanisms in all three environments.
