ASTRO In the literature: contested

Are globular clusters survivors of young massive clusters in early galaxies?

In plain words

The James Webb Space Telescope sees very dense young star clusters in galaxies less than a billion years after the Big Bang. Whether today's globular clusters are the survivors of such clusters, or needed special conditions to form, is not known.

Precise statement

Decide whether present-day globular clusters formed by the same process as young massive clusters today, in high-pressure, gas-rich disks at $z \sim 2\ \text{to}\ 10$, followed by tidal disruption of most clusters, or require a distinct channel (for example formation in dark matter minihalos or as nuclei of accreted dwarfs). The model must reproduce the globular-cluster mass function, the age-metallicity relation of Milky Way clusters and the number of clusters per unit galaxy mass.

What would settle it

JWST measurements of the mass function, sizes and formation efficiency of lensed clusters at $z \sim 2\ \text{to}\ 10$, compared with cosmological simulations that follow cluster formation and disruption to $z = 0$.

Status in the literature

Unverified note

Bound, dense clusters were reported in a lensed galaxy at $z \sim 10$, the Cosmic Gems arc (Adamo et al., Nature, 2024), supporting early formation without fixing the channel.

See also