Galaxy Threshing and the Formation of Ultracompact Dwarf Galaxies

By Kenji Bekki, W. Couch, Michael Drinkwater. 2001

147 citations recorded by the source corpus.

Recent spectroscopic and morphological observational studies of galaxies around NGC 1399 in the Fornax Cluster have discovered several "ultracompact dwarf" galaxies with intrinsic sizes of ~100 pc and absolute B-band magnitudes ranging from -13 to -11 mag. In order to elucidate the origin of these enigmatic objects, we perform numerical simulations on the dynamical evolution of nucleated dwarf galaxies orbiting NGC 1399 and suffering from its strong tidal gravitational field. Adopting a plausible scaling relation for dwarf galaxies, we find that the outer stellar components of a nucleated dwarf are totally removed. This is due to them being tidally stripped over the course of several passages past the central region of NGC 1399. The nucleus, however, manages to survive. We also find that the size and luminosity of the remnant are similar to those observed for ultracompact dwarf galaxies, if the simulated precursor nucleated dwarf has a mass of ~108 M☉. These results suggest that ultracompact dwarf galaxies could have previously been more luminous dwarf spheroidal or elliptical galaxies with rather compact nuclei.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5c79f25c61565881993cca27d0a44aae0f4c7ee2

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In Astronomy and Astrophysics

Citations in the corpus

Galaxy threshing and the origin of ultra-compact dwarf galaxies in the Fornax cluster (2003, methodology): “MB and ep are the most important parameters in determining whether a dE,N can be morphologically transformed into a UCD by galaxy threshing (Bekki et al. 2001); we therefore focus in most detail on the dependences our results have on these two parameters.”
The ACS Virgo Cluster Survey. VII. Resolving the Connection between Globular Clusters and Ultracompact Dwarf Galaxies (2005, background): “Taken together, the assembled evidence is consistent with the formation of at least some UCDs through galaxy threshing (Bekki et al. 2001).”
WIDE-FIELD PRECISION KINEMATICS OF THE M87 GLOBULAR CLUSTER SYSTEM (2011, background): “One is that the UCDs are the remnant cores of larger galaxies which have been stripped through a process such as tidal threshing (e.g., Bassino et al. 1994; Bekki et al. 2001).”
THE RELATIONSHIPS AMONG COMPACT STELLAR SYSTEMS: A FRESH VIEW OF ULTRACOMPACT DWARFS (2011, background): “The fourth is that they are stripped galactic nuclei (e.g., Bekki et al. 2001; Goerdt et al. 2008).”