A Population of Compact Elliptical Galaxies Detected with the Virtual
  Observatory
  Compact elliptical galaxies are characterized by small sizes and high stellar
densities. They are thought to form through tidal stripping of massive
progenitors. However, only a handful of them were known, preventing us from
understanding the role played by this mechanism in galaxy evolution. We present
a population of 21 compact elliptical galaxies gathered with the Virtual
Observatory. Follow-up spectroscopy and data mining, using high-resolution
images and large databases, show that all the galaxies exhibit old metal-rich
stellar populations different from those of dwarf elliptical galaxies of
similar masses but similar to those of more massive early-type galaxies,
supporting the tidal stripping scenario. Their internal properties are
reproduced by numerical simulations, which result in compact dynamically hot
remnants resembling the galaxies in our sample.
