Bibcode
Rys, A.; Falcón-Barroso, J.; van de Ven, G.
Referencia bibliográfica
American Astronomical Society, AAS Meeting #221, #111.04
Fecha de publicación:
1
2013
Número de citas
1
Número de citas referidas
1
Descripción
Dwarf elliptical galaxies (dEs) are the most common galaxy class in
dense environments. They are also a surprisingly inhomogenous class,
which has made it challenging both to relate different dE subtypes to
each other, as well as place the whole class in the larger context of
galaxy assembly and (trans)formation processes. Here we will show the
effects of environmental evolution on Virgo Cluster and field dEs,
presenting the first large-scale integral-field spectroscopic (SAURON)
data for this galaxy class. Our sample consists of 12 galaxies and no
two of them are alike. We find that the level of rotation is not tied to
flattening; we observe kinematic twists; we discover large-scale
kinematically-decoupled components; we see varying gradients in
line-strength maps. This great variety of morphological, kinematic, and
stellar population parameters supports the claim that dEs are defunct
dwarf spiral/irregular galaxies and points to a formation scenario that
allows for a stochastic shaping of galaxy properties. The combined
influence of ram-pressure stripping and harassment fulfils this
requirement, still, their exact impact is not yet understood. We thus
further investigate the properties of our sample by performing a
detailed comprehensive analysis of its kinematic, dynamical, and stellar
population properties. We infer the total (dark and baryonic) matter
distribution by fitting the observed stellar velocity and velocity
dispersion with the solutions of the Jeans equations. We obtain 2D age,
metallicity, and enrichment information from line-strength analysis. We
then tie these results to the galaxies' intrinsic (i.e. deprojected)
locations in the cluster with the use of surface-brightness fluctuation
distances. This step is essential to providing unbiased correlations
with the local environment density. We show that the dark matter
fraction, unlike the level of rotational support, appears to correlate
with the clustrocentric distance, and that our dwarfs have kinematic
properties similar to those of fast-rotating giant early-type galaxies.