  The properties of satellite dwarf galaxies pose important empirical
constraints to verify cosmological models on galaxy scales. Their phase-space
correlations, in particular, offer interesting insights into various models.
Next to the planes-of-satellites phenomenon, the lopsided distribution of
satellites relative to their host galaxy has been studied observationally and
in cosmological simulations. It is still unclear how observed lopsidedness
aligns with expectations from simulations. We measure lopsidedness in observed
isolated satellite systems using six different metrics. We study 47 systems
from the MATLAS survey beyond the Local Volume (LV) as well as 21 LV satellite
systems from the ELVES survey. We find that the so-called wedge metric,
counting the number of dwarfs in wedges with varying opening angles, is best
suited to capture a system's overall lopsidedness. Under this metric, our
analysis reveals that ~16 percent of the tested satellite systems exhibit a
statistically significant degree of lopsidedness when compared to systems with
randomly generated satellite position angles. This presents a notable excess
over the expected 5% (2 sigma level) of significantly lopsided systems in a
sample with no overall inherent lopsidedness. However, using multiple metrics
provides a more complete picture. Combining all tested metrics, the number of
significantly lopsided systems increases to ~21 percent. Contrary to recent
results from the literature, we find more lopsided systems among the red
early-type galaxies in the MATLAS survey compared to the mostly blue late-type
hosts in ELVES. We further find that satellite galaxies at larger distances
from the host, potentially recently accreted, are likely the primary
contributors to the reported excess of lopsidedness. Our results enable
comparisons with similar systems in simulations to assess consistency with the
standard model.
