Galaxy threshing and the origin of ultra-compact dwarf galaxies in the Fornax cluster

Bekki, K., Couch, W. J., Drinkwater, M. J. and Shioya, Y. (2003) Galaxy threshing and the origin of ultra-compact dwarf galaxies in the Fornax cluster. Monthly Notices of The Royal Astronomical Society, 344 2: 399-411. doi:10.1046/j.1365-8711.2003.06916.x

Author Bekki, K.
Couch, W. J.
Drinkwater, M. J.
Shioya, Y.
Title Galaxy threshing and the origin of ultra-compact dwarf galaxies in the Fornax cluster
Journal name Monthly Notices of The Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
Publication date 2003-09
Sub-type Article (original research)
DOI 10.1046/j.1365-8711.2003.06916.x
Open Access Status DOI
Volume 344
Issue 2
Start page 399
End page 411
Total pages 13
Editor A. C. Fabian
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Collection year 2003
Language eng
Abstract A recent all-object spectroscopic survey centred on the Fornax cluster of galaxies has discovered a population of subluminous and extremely compact members, called 'ultra-compact dwarf' (UCD) galaxies. In order to clarify the origin of these objects, we have used self-consistent numerical simulations to study the dynamical evolution a nucleated dwarf galaxy would undergo if orbiting the centre of the Fornax cluster and suffering from its strong tidal gravitational field. We find that the outer stellar components of a nucleated dwarf are removed by the strong tidal field of the cluster, whereas the nucleus manages to survive as a result of its initially compact nature. The developed naked nucleus is found to have physical properties (e. g. size and mass) similar to those observed for UCDs. We also find that although this formation process does not have a strong dependence on the initial total luminosity of the nucleated dwarf, it does depend on the radial density profile of the dark halo in the sense that UCDs are less likely to be formed from dwarfs embedded in dark matter haloes with central 'cuspy' density profiles. Our simulations also suggest that very massive and compact stellar systems can be rapidly and efficiently formed in the central regions of dwarfs through the merging of smaller star clusters. We provide some theoretical predictions on the total number and radial number density profile of UCDs in a cluster and their dependencies on cluster masses.
Keyword Astronomy & Astrophysics
Galaxies : Clusters : General
Galaxies : Clusters : Individual : Fornax
Galaxies : Dwarf
Galaxies : Elliptical And Lenticular, Cd
Galaxies : Formation
Galaxies : Interactions
Virgo Cluster
Elliptical Galaxies
Luminosity Function
Local Group
Q-Index Code C1

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Created: Wed, 15 Aug 2007, 02:20:36 EST