Query : 2023A&A...671L...7R

2023A&A...671L...7R - Astronomy and Astrophysics, volume 671, L7 (2023/3-1)

Evidence for globular cluster collapse after a dwarf-dwarf merger: A potential nuclear star cluster in formation.


Abstract (from CDS):

Direct observational evidence for the creation of nuclear star clusters (NSCs) is needed to support the proposed scenarios for their formation. We analysed the dwarf galaxy UGC 7346, located in the peripheral regions of the Virgo Cluster, to highlight a series of properties that indicate the formation of a NSC caught in its earlier stages. First, we report on remnants of a past interaction in the form of diffuse streams or shells, suggesting a recent merging of two dwarf galaxies with a 1:5 stellar mass ratio. Second, we identify a number of globular cluster (GC) candidates that are broadly compatible in colour with the main component that is both more extended and more massive. Strikingly, we find these GCs candidates to be highly concentrated towards the centre of the galaxy (RGC = 0.41 Re). We suggest that the central concentration of the GCs is likely produced by the dynamical friction of this merger. This would make UGC 7346 a unique case of a galaxy caught in the earlier stages of NSC formation. The formation of NSCs due to collapse of GCs by dynamical friction in dwarf mergers would provide a natural explanation of the environmental correlations found for the nucleation fraction for early-type dwarf galaxies, whereby denser environments host galaxies with a higher nucleation fraction.

Abstract Copyright: © The Authors 2023

Journal keyword(s): galaxies: dwarf - galaxies: star clusters: general - galaxies: structure

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 ACO S 373 ClG 03 38 29.4 -35 27 08           ~ 1831 0
2 UGC 7346 GiG 12 18 41.792 +17 43 08.73   15.5       ~ 23 0
3 NAME Virgo Cluster ClG 12 26 32.1 +12 43 24           ~ 6660 0
4 ACO 1656 ClG 12 59 44.40 +27 54 44.9           ~ 4816 2

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