Bibcode
Ryś, A.; van de Ven, G.; Falcón-Barroso, J.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 439, Issue 1, p.284-299
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3
2014
Citations
44
Refereed citations
42
Description
We present the dynamical analysis of a sample of 12 dwarf elliptical
(dE) galaxies for which we have obtained SAURON large-scale
two-dimensional spectroscopic data. We construct Jeans axisymmetric
models and obtain total dynamical masses enclosed within one effective
radius. We use the obtained values to show that the validity of the
dynamical scaling relations of massive early-type galaxies can be
extended to these low-mass systems, except that dEs seem to contain
relatively larger fraction of dark matter in their inner parts. We then
demonstrate that dE galaxies have lower angular momenta than the
present-day analogues of their presumed late-type progenitors, and we
show that dE circular velocity curves are steeper than the rotation
curves of galaxies with equal and up to an order of magnitude higher
luminosity. This requires a transformation mechanism that is not only
able to lower the angular momentum but also one that needs to account
for increased stellar concentration. Additionally, we match the dark
matter fraction of our galaxies to their location in the Virgo Cluster
and see that galaxies in the cluster outskirts tend to have a higher
dark-to-stellar matter ratio. Transformation due to tidal harassment is
able to explain all of the above, unless the dE progenitors were already
compact and had lower angular momenta at higher redshifts.
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