Mechanism of positive metallicity gradients in GC-rich dwarf ellipticals

Determine whether globular-cluster-rich dwarf elliptical galaxies produce positive stellar metallicity gradients through the same feedback-driven and globular-cluster-disruption mechanisms proposed for globular-cluster-rich ultra-diffuse galaxies.

Background

The paper proposes that positive metallicity gradients in some UDGs and NUDGEs may result from the combined effects of an early, centrally concentrated burst of star formation, feedback-driven outward propagation of enriched gas, and the inward migration and tidal disruption of metal-poor globular clusters. Disrupted globular-cluster stars deposited preferentially toward the galaxy center could make the inner regions more metal-poor than the outskirts.

The authors note that the same interpretation might apply to globular-cluster-rich dwarf elliptical galaxies, but the comparison sample is dominated by globular-cluster-poor systems that generally exhibit conventional negative metallicity gradients. Whether the proposed mechanism operates in globular-cluster-rich dwarf ellipticals therefore remains unresolved.

References

Whether equivalent GC-rich dE galaxies follow the same mechanism remains uncertain.

— Diffuse Dwarf Galaxies in Galaxy Clusters: I. Stellar Populations and Radial Gradients  (2608.17375 - Levitskiy et al., 18 Aug 2026) in Section 4.3, “What drives the positive metallicity gradients?”