Formation of ultra-compact dwarf galaxies: tests of the galaxy threshing scenario in Fornax

Thomas, P.A., Drinkwater, M.J. and Evstigneeva, E. (2008) Formation of ultra-compact dwarf galaxies: tests of the galaxy threshing scenario in Fornax. Monthly Notices of Royal Astronomical Society, 389 1: 102-112. doi:10.1111/j.1365-2966.2008.13543.x

Author Thomas, P.A.
Drinkwater, M.J.
Evstigneeva, E.
Title Formation of ultra-compact dwarf galaxies: tests of the galaxy threshing scenario in Fornax
Journal name Monthly Notices of Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
Publication date 2008-07-24
Year available 2008
Sub-type Article (original research)
DOI 10.1111/j.1365-2966.2008.13543.x
Open Access Status DOI
Volume 389
Issue 1
Start page 102
End page 112
Total pages 11
Editor Fabian, A.C.
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Subject 1912 Space and Planetary Science
Abstract This paper investigates the possibility that ultra-compact dwarf (UCD) galaxies in the Fornax cluster are formed by the threshing of nucleated, early-type dwarf galaxies (hereafter dwarf galaxies). Similar to the results of Côté et al. for the Virgo cluster, we show that the Fornax cluster observations are consistent with a single population in which all dwarfs are nucleated, with a ratio of nuclear to total magnitude that varies slowly with magnitude. Importantly, the magnitude distribution of the UCD population is similar to that of the dwarf nuclei in the Fornax cluster. The joint population of UCDs and the dwarfs from which they may originate is modelled and shown to be consistent with a Navarro, Frenk & White (NFW) profile with a characteristic radius of 5 kpc. Furthermore, a steady-state dynamical model reproduces the known mass profile of Fornax. However, there are a number of peculiarities in the velocity dispersion data that remain unexplained. The simplest possible threshing model is tested, in which dwarf galaxies move on orbits in a static cluster potential and are threshed if they pass within a radius at which the tidal force from the cluster exceeds the internal gravity at the core of their dark matter halo. This fails to reproduce the observed fraction of UCDs at radii greater than 30 kpc from the core of Fornax.
Keyword Astronomy & Astrophysics
Astronomy & Astrophysics
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP0557676
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Mathematics and Physics
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Citation counts: TR Web of Science Citation Count  Cited 19 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 19 times in Scopus Article | Citations
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Created: Wed, 25 Mar 2009, 21:16:39 EST by Jo Hughes on behalf of School of Mathematics & Physics