- [*] Rotation Versus Anisotropy in Dwarf Elliptical Galaxies
- Geha M., Guhathakurta P., van der Marel R.P.
- BAAS, in press, 2003 (AAS Meeting 201, 26.02)
- © 2003. The American Astronomical Society.
All Rights Reserved.
We present velocity and velocity dispersion profiles for twelve dwarf
elliptical (dE) galaxies in the Virgo Cluster observed with the Keck
telescope and Echelle Spectrograph and Imager (ESI). In combination
with previous measurements, we find that 11 of 25 Virgo dEs with
resolved kinematics are roughly consistent with rotational flattening,
while the remaining dEs have no detectable major axis
rotation. Despite this apparent dichotomy in rotational properties,
the two types of dEs are virtually identical in all available
photometric properties; the only exception is that the rotating
galaxies have, on average, slightly higher surface brightness. Both
sets of dEs are confined to a small region of the Fundamental Plane,
suggesting that they share a similar formation history. The
environments of both classes of dEs appear to be diverse in terms of
their proximity to larger galaxies in real or velocity space within
Finally, we compare the Virgo Cluster dEs to five dEs in lower density
galaxy group environments. These group galaxies are morphologically
classified as "dE", but have higher central surface brightnesses
placing them in the zone of the Fundamental Plane between other known
dEs and normal low luminosity ellipticals. All of these group "dE"
galaxies show significant stellar rotation; one object is
kinematically peculiar with evidence of a counter-rotating core. Three
of the five group "dEs" have emission lines. These data suggest that
environment plays a significant role in the evolution of dE galaxies.
Return to my bibliography.
Return to my home page.
Last modified November 29, 2002.
Roeland van der Marel,