Star-Forming Galaxies at z~2 and the Formation of the Metal-Rich Globular Cluster Population

TL;DR

This paper proposes that super star-forming clumps at z~2 are the formation sites of metal-rich globular clusters, linking high-redshift galaxy structures to local globular cluster populations.

Contribution

It demonstrates that the stellar populations, spatial distribution, and kinematics of these clumps match those of local metal-rich globular clusters, suggesting a formation scenario.

Findings

Clumps' stellar populations match local metal-rich globular clusters.

Spatial and kinematic properties are consistent with bulge and disk formation.

The formation scenario reproduces observed globular cluster numbers and mass spectra.

Abstract

We examine whether the super star-forming clumps (R~1-3 kpc; M~10^8-10^9.5 Msun) now known to be a key component of star-forming galaxies at z~2 could be the formation sites of the locally observed old globular cluster population. We find that the stellar populations of these super star-forming clumps are excellent matches to those of local metal-rich globular clusters. Moreover, this globular cluster population is known to be associated with the bulges / thick disks of galaxies, and we show that its spatial distribution and kinematics are consistent with the current understanding of the assembly of bulges and thick disks from super star-forming clumps at high redshift. Finally, with the assumption that star formation in these clumps proceeds as a scaled-up version of local star formation in molecular clouds, this formation scenario reproduces the observed numbers and mass spectra of metal-rich globular clusters. The resulting link between the turbulent and clumpy disks observed in high-redshift galaxies and a local globular cluster population provides a plausible co-evolutionary scenario for several of the major components of a galaxy: the bulge, the thick disk, and one of the globular cluster populations.