Abstract We perform a cosmological zoom-in simulation of a massive galaxy (Mₛ 10^10 M_ at z ∼ 10) using the GIZMO code. By employing 3 pc resolution and a 3. 4 Myr supernova feedback delay, we capture the feedback-free starbursts (FFB) in clusters. The simulation reproduces FFB model predictions and super-bright galaxies observed by JWST. At z ∼ 10, cold streams feed a compact galaxy (R ₄ 1 kpc), with stellar and surface densities (10⁵ cm^-3, 10⁵ M_ pc^-2) exceeding FFB thresholds. The global star-formation efficiency (SFE) is ϵs ∼ 0. 2–0. 3, associated with a fluctuating star-formation history. We identified over 105 star clusters (M 10^4. 5 M_) with a nearly scale-free mass distribution (dN/dlog M∝M−1. 06). Approximately 90% of star formation occurs in clusters, which at a given time constitute 30\!-\!40~{\ per\ cent} of the total stellar mass. The star formation in most of the clusters of masses 10⁷ M_, occurs in bursts of 3 Myr and a local SFE ∼0. 5 ± 0. 2. Cluster metallicities (−2. 01 log (Z/Z⊙) −0. 45) indicate rapid baryon recycling. Feedback-driven outflows exhibit typical temperature of 10⁷ K and typical velocities of 2000 km\ s^-1. In the highly dynamic central 1 kpc, clusters undergo rapid orbital decay and merge to assemble the oblate nuclear stellar cluster. Cluster shapes range from oblate to prolate, with a triaxial median. These clusters are consistent with JWST observations, and a fraction of them may survive to yield the globular clusters (GCs) at low redshifts.
Chen et al. (Thu,) studied this question.