English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Globular clusters can form inside their host galaxies at high redshift whengas densities were higher and gas-rich mergers were common. They can also forminside lower-mass galaxies that have since been accreted and tidally disrupted,leaving their globular cluster complement bound to higher-mass halos. We arguethat the age-metallicity-specific orbital energy relation in a galaxy'sglobular cluster system can be used to identify its origin. Gas-rich mergersshould produce tightly bound systems in which metal-rich clusters are youngerthan metal-poor clusters. Globular clusters formed in massive disks and thenscattered into a halo should have no relationship between age and specificorbital energy. Accreted globular clusters should produce weakly bound systemsin which age and metallicity are correlated with each other but inverselycorrelated with specific orbital energy. We use precise relative ages,self-consistent metallicities, and space-based proper motion-informed orbits toshow that the Milky Way's metal-poor globular cluster system lies in a plane inage-metallicity-specific orbital energy space. We find that relatively young ormetal-poor globular clusters are weakly bound to the Milky Way, whilerelatively old or metal-rich globular clusters are tightly bound to the Galaxy.While metal-rich globular clusters may be formed either in situ or ex situ, ourresults suggest that metal-poor clusters formed outside of the Milky Way innow-disrupted dwarf galaxies. We predict that this relationship between age,metallicity, and specific orbital energy in a $L^{*}$ galaxy's globular clustersystem is a natural outcome of galaxy formation in a $\Lambda$CDM universe.

the astronomical journal

The Age-Metallicity-Specific Orbital Energy Relation for the Milky Way's  Globular Cluster System Confirms the Importance of Accretion for Its  Formation