On the accretion of a new group of galaxies onto Virgo: I. Internal
  kinematics of nine in-falling dEs
  Galaxy environment has been shown to play an important role in transforming
late-type, star-forming galaxies to quiescent spheroids. This transformation is
expected to be more severe for low-mass galaxies (M < $10^{10}$ \(M_\odot\)) in
dense galaxy groups and clusters, mostly due to the influence of their past
host halos (also known as pre-processing) and their present-day environments.
For the first time, in this study, we investigate a sample of nine early-type
dwarf galaxies (dEs) that were accreted as a likely bound group onto the Virgo
galaxy cluster about 2-3 Gyr ago. Considering this special condition, these
nine dEs may provide a test bed for distinguishing between the influence of the
Virgo galaxy cluster and the effects of the previous host halo on their current
properties. Specifically, we use VLT/MUSE integral-field unit spectra to derive
their kinematics and specific angular momentum ($\lambda_{R}$) profiles. We
observe a spread in the $\lambda_{R}$ profiles of our sample dEs, finding that
the $\lambda_{R}$ profiles of half of them are as high as those of low-mass
field galaxies. The remaining dEs exhibit $\lambda_{R}$ profiles as low as
those of Virgo dEs that were likely accreted longer ago. Moreover, we detect
nebular emission in one dE with a gas velocity offset suggesting ongoing gas
stripping in Virgo. We suggest that the low-$\lambda_{R}$ dEs in our sample
were processed by their previous host halo, prior to their infall to Virgo, and
that the high-$\lambda_{R}$ dEs may be experiencing ram pressure stripping in
Virgo.
