MNRAS-2008-Thomas-102-12.pdf (610.47 kB)
Formation of ultra-compact dwarf galaxies: tests of the galaxy threshing scenario in Fornax
journal contribution
posted on 2023-06-08, 07:33 authored by Peter ThomasPeter Thomas, M J Drinkwater, E EvstigneevaThis 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.
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- Published
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- Published version
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Monthly Notices of the Royal Astronomical SocietyISSN
0035-8711External DOI
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1Volume
389Page range
102-112Pages
11.0Department affiliated with
- Physics and Astronomy Publications
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- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2012-02-06First Open Access (FOA) Date
2016-03-22First Compliant Deposit (FCD) Date
2017-03-07Usage metrics
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