The numerical frontier of the high-redshift Universe

TL;DR

This review summarizes the progress in understanding high-redshift star and galaxy formation, emphasizing numerical simulations of early Universe structures, star formation processes, feedback mechanisms, and galaxy assembly since 2000.

Contribution

It provides a comprehensive overview of recent theoretical and simulation-based advances in modeling the formation of the first stars and galaxies in the early Universe.

Findings

Insights into the formation of the first stars in minihalos.

Understanding of feedback effects from the first stars.

Progress in simulating early galaxy assembly.

Abstract

The first stars are believed to have formed a few hundred million years after the big bang in so-called dark matter minihalos with masses ~10^6 M_sun. Their radiation lit up the Universe for the first time, and the supernova explosions that ended their brief lives enriched the intergalactic medium with the first heavy elements. Influenced by their feedback, the first galaxies assembled in halos with masses ~10^8 M_sun, and hosted the first metal-enriched stellar populations. In this review, I summarize the theoretical progress made in the field of high-redshift star and galaxy formation since the turn of the millennium, with an emphasis on numerical simulations. These have become the method of choice to understand the multi-scale, multi-physics problem posed by structure formation in the early Universe. In the first part of the review, I focus on the formation of the first stars in minihalos - in particular the post-collapse phase, where disk fragmentation, protostellar evolution, and radiative feedback become important. I also discuss the influence of additional physical processes, such as magnetic fields and streaming velocities. In the second part of the review, I summarize the various feedback mechanisms exerted by the first stars, followed by a discussion of the first galaxies and the various physical processes that operate in them.