Galaxy morphology is also influenced by environment, and clusters are especially efficient at transforming galaxies. The discovery of weak non-axysimmetric structures (bars, spirals, and warps) and disk-like kinematics in bright Virgo dwarf elliptical and lenticular galaxies (dE/dSph/dS0) indicates that they may have late-type progenitors. Using N-body simulations we followed the evolution of disk galaxies within a ΛCDM cluster, where the hierarchical growth and galaxy harassment are modeled self-consistently. We found that most of the galaxies underwent significant morphological transformation, even at the outskirts of the cluster, and moved through the Hubble sequence from late-type disks to dwarf spheroidals. None of the disks were completely destroyed and cannot therefore be the progenitors of ultra compact dwarf galaxies. We compared unsharp-masked images and the projected kinematics of our models with observations and found good agreement in both.

Figure 1 shows the evolution of the stellar surface density of a galaxy infalling into a cluster from z = 0.3 to z ∼ 0. The color scale is logarithmic. The top panels represent the face on projection while the corresponding edge on projection is shown on the bottom. A bar is induced by encounters and this experiences a buckling/bending instability. Coupled with tidal stripping, which can extend down to the edges of the bar, the system becomes more spheroidal. Fossil evidence of the intial disk is preserved in the form of weak spirals, bars, and significant rotation.

Figure 2 shows the intracluster light produced by tidal processes. The color contrast is chosen in such a way as to point out the low density regions (light green, corresponding to a surface brightness μ 30 mag arcsec^-2) and the traces of stellar streams.

Reference: Mastropietro, et al. (2005).