Evidence of star cluster migration and merger in dwarf galaxies
arXiv:2504.06749 · doi:10.1038/s41586-025-08783-9
Abstract
Nuclear star clusters (NSCs) are the densest stellar systems in the Universe. They can be found at the center of all galaxy types, but tend to favor galaxies of intermediate stellar mass around 10M[1, 2]. Currently, two main processes are under debate to explain their formation: in-situ star-formation from gas infall[3] and migration and merging of globular clusters (GCs) caused by dynamical friction[4]. Studies[5-9] of NSC stellar populations suggest that the former predominates in massive galaxies, the latter prevails in dwarf galaxies, and both contribute equally at intermediate mass. However, up to now, no ongoing merger of GCs has yet been observed to confirm this scenario. Here we report the serendipitous discovery of five dwarf galaxies with complex nuclear regions, characterized by multiple nuclei and tidal tails, using high resolution images from the Hubble Space Telescope. These structures have been reproduced in complementary N-body simulations, supporting the interpretation that they result from migrating and merging of star clusters. The small detection rate and short simulated timescales (below 100 Myr) of this process may explain why this has not been observed previously. This study highlights the need of large surveys with high resolution to fully map the migration scenario steps.
arXiv commentPublished in Nature. 19 pages, 6 figures, 1 table
References in corpus (28)
- Cosmological Hydrodynamics with Adaptive Mesh Refinement: a new high resolution code called RAMSES
- The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
- Dark Matter Scaling Relations
- Nuclear Star Clusters
- The Atlas3D project -- XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images
- An accurate physical model for halo concentrations
- Nuclear star clusters in 228 spiral galaxies in the HST/WFPC2 archive: catalogue and comparison to other stellar systems
- The ACS Fornax Cluster Survey. VI. The Nuclei of Early-Type Galaxies in the Fornax Cluster
- The Next Generation Virgo Cluster Survey. XXIII. Fundamentals of nuclear star clusters over seven decades in galaxy mass
- Constraining the role of star cluster mergers in nuclear cluster formation: Simulations confront integral-field data
- The M31 globular cluster system: ugriz and K-band photometry and structural parameters
- New insights on the formation of nuclear star clusters
- A catalog of merging dwarf galaxies in the local universe
- Structure and morphology of the MATLAS dwarf galaxies and their central nuclei
- Ultra diffuse galaxies in the MATLAS low-to-moderate density fields
- Diversity of nuclear star cluster formation mechanisms revealed by their star formation histories
- Nuclear star cluster formation in star-forming dwarf galaxies
- Disentangling the formation mechanisms of nuclear star clusters
- The Next Generation Fornax Survey (NGFS): VII. A MUSE view of the nuclear star clusters in Fornax dwarf galaxies
- The Binary Nucleus in VCC 128: A Candidate Supermassive Black Hole in a Dwarf Elliptical Galaxy
- Tidal Interaction as the origin of early-type dwarf galaxies in group environment
- HI observations of the MATLAS dwarf and ultra-diffuse galaxies
- Starbursting Nuclei in Old Dwarf Galaxies
- Are we observing a NSC in course of formation in the NGC 4654 galaxy?
- MCG+08-22-082: A double core and boxy appearance dwarf lenticular galaxy as suspected to be a merger remnant
- Double nuclei in NGC 908 and NGC 1187
- Growing a nuclear star cluster from star formation and cluster mergers: The JWST NIRSpec view of NGC 4654
- Dwarf Galaxies in the MATLAS Survey: Hubble Space Telescope Observations of the Globular Cluster Systems of 74 Ultra Diffuse Galaxies