The First Supernova Explosions: Energetics, Feedback, and Chemical Enrichment

TL;DR

This study uses 3D simulations to explore the expansion, feedback, and chemical enrichment effects of a primordial supernova in the early universe, revealing its impact on host halos and neighboring structures.

Contribution

It provides detailed insights into the dynamics and feedback of a pair-instability supernova in a high-redshift cosmological context, including shock morphology and metal enrichment.

Findings

The supernova remnant expands to about 2.5 kpc over a Hubble time at z=20.

The host halo is completely disrupted, halting star formation for at least 200 Myr.

Metal line cooling is negligible; the interior bubble expands adiabatically.

Abstract

We perform three-dimensional smoothed particle hydrodynamics simulations in a realistic cosmological setting to investigate the expansion, feedback, and chemical enrichment properties of a 200 M_sun pair-instability supernova in the high-redshift universe. We find that the SN remnant propagates for a Hubble time at z = 20 to a final mass-weighted mean shock radius of 2.5 kpc (proper), roughly half the size of the HII region, and in this process sweeps up a total gas mass of 2.5*10^5 M_sun. The morphology of the shock becomes highly anisotropic once it leaves the host halo and encounters filaments and neighboring minihalos, while the bulk of the shock propagates into the voids of the intergalactic medium. The SN entirely disrupts the host halo and terminates further star formation for at least 200 Myr, while in our specific case it exerts positive mechanical feedback on neighboring minihalos by shock-compressing their cores. In contrast, we do not observe secondary star formation in the dense shell via gravitational fragmentation, due to the previous photoheating by the progenitor star. We find that cooling by metal lines is unimportant for the entire evolution of the SN remnant, while the metal-enriched, interior bubble expands adiabatically into the cavities created by the shock, and ultimately into the voids with a maximum extent similar to the final mass-weighted mean shock radius. Finally, we conclude that dark matter halos of at least M_vir > 10^8 M_sun must be assembled to recollect all components of the swept-up gas.