Bibcode
Toloba, E.; Boselli, A.; Peletier, R. F.; Falcón-Barroso, J.; van de Ven, G.; Gorgas, J.
Bibliographical reference
Astronomy and Astrophysics, Volume 548, id.A78, 13 pp.
Advertised on:
12
2012
Journal
Citations
37
Refereed citations
37
Description
We place our sample of 18 Virgo dwarf early-type galaxies (dEs) on the
(V - K)e-velocity dispersion, Faber-Jackson, and fundamental
plane (FP) scaling relations for massive early-type galaxies (Es). We
use a generalized velocity dispersion, which includes rotation, to be
able to compare the location of both rotationally and pressure supported
dEs with those of early and late-type galaxies. We find that dEs seem to
bend the Faber-Jackson relation of Es to lower velocity dispersions,
being the link between Es and dwarf spheroidal galaxies (dSphs).
Regarding the FP relation, we find that dEs are significantly offset
with respect to massive hot stellar systems, and re-casting the FP into
the so-called κ-space suggests that this offset is related to dEs
having a total mass-to-light ratio higher than Es but still
significantly lower than dSph galaxies. Given a stellar mass-to-light
ratio based on the measured line indices of dEs, the FP offset allows us
to infer that the dark matter fraction within the half light radii of
dEs is on average ≳42% (uncertainties of 17% in the K band and 20%
in the V band), fully consistent with an independent estimate in an
earlier paper in this series. We also find that dEs in the
size-luminosity relation in the near-infrared, like in the optical, are
offset from early-type galaxies, but seem to be consistent with
late-type galaxies. We thus conclude that the scaling relations show
that dEs are different from Es, and that they further strengthen our
previous findings that dEs are closer to and likely formed from
late-type galaxies.
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