  We study the internal response of a galaxy to an unbound encounter and
present a survey of orbital parameters covering typical encounters in different
galactic environments. Overall, we conclude that relatively weak encounters by
low-mass interloping galaxies can cause observable distortions in the
primaries. The resulting asymmetries may persist long after the interloper is
evident. We focus our attention on the production of structure in dark halos
and in cluster ellipticals. Any distortion produced in a dark halo can distort
the embedded stellar disk, possibly leading to the formation of lopsided and
warped disks. Features excited in an elliptical are directly observable and we
predict that asymmetries in the morphologies of these systems can be produced
by relatively small perturbers. We use these detailed results to predict the
distribution of the $A$ parameter defined by Abraham et al. and the shift
between the center of mass of the primary system and the position of the peak
of density for a range of environments. We find that high-density, low-velocity
dispersion environments are more likely to host galaxies with significant
asymmetries. Our distribution for the $A$ parameter is in good agreement with
the range spanned by the observed values for local galaxy clusters and for
distant galaxies in the MDS and in the HDF.Finally, we propose a generalized
asymmetry parameter $A(r)$ which provides detailed information on the radial
structure of the asymmetry produced by the mechanism explored in our work.
(abridged)
