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Internal Dynamics of the Most Luminous Fornax Cluster UCD

Published online by Cambridge University Press:  11 July 2011

M.J. Frank*
Affiliation:
European Southern Observatory, Garching, Germany Astronomisches Rechen-Institut, Zentrum für Astronomie, Universität Heidelberg, Germany
M. Hilker
Affiliation:
European Southern Observatory, Garching, Germany
S. Mieske
Affiliation:
European Southern Observatory, Vitacura, Santiago, Chile
H. Baumgardt
Affiliation:
School of Mathematics and Physics, University of Queensland, Australia
E.K. Grebel
Affiliation:
Astronomisches Rechen-Institut, Zentrum für Astronomie, Universität Heidelberg, Germany
*
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Abstract

We present the internal kinematics of UCD3, the brightest known ultra-compact dwarf galaxy (UCD) in the Fornax cluster and the first UCD with spatially resolved spectroscopy. Based on seeing-limited observations with VLT/FLAMES, we measure a velocity field showing the signature of weak rotation and a radial velocity dispersion profile that is flatter than expected from an isotropic Jeans model where mass follows light. We find that both, a strongly anisotropic velocity distribution, and a dark matter component as predicted by simulations of galaxy threshing, can explain the observed flattening.

Type
Research Article
Copyright
© EAS, EDP Sciences, 2011

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References

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