The high-redshift formation of metal-poor globular cluster systems

We present a formation scenario for metal-poor globular cluster systems. We assume old metal-poor globular clusters are formed only prior to reionization (at z similar to 7) in merging proto-galactic building blocks; the building blocks assemble hierarchically into larger structures such as galaxies. We additionally assume that globular cluster formation is suppressed immediately after reionization: subsequent globular cluster formation results in a gap in the metallicity distributions of globular cluster systems. We describe generic predictions of the model with regard to the "blue specific frequency problem" and the spatial distribution of metal-poor globular cluster systems. We conclude with a discussion of the range of applications for this model.