The Destruction of Cosmological Minihalos by Primordial Supernovae

TL;DR

This study uses numerical simulations to explore how primordial supernovae impact early minihalos, revealing their potential to destroy halos, disperse metals, and influence early galaxy formation and black hole growth.

Contribution

It provides detailed simulations of primordial supernovae in minihalos, showing their effects on halo disruption, metal dispersal, and subsequent star formation, which advances understanding of early universe evolution.

Findings

Supernovae can destroy halos less than 10^7 solar masses.

Pair instability supernovae can disrupt larger halos.

Explosions in H II regions enable second-generation star formation.

Abstract

We present numerical simulations of primordial supernovae in cosmological minihalos at $z \sim$ 20. We consider Type II supernovae, hypernovae, and pair instability supernovae (PISN) in halos from 6.9 $\times$ 10$^5$ - 1.2 $\times$ 10$^7$ $\Ms$, those in which Population III stars are expected to form via H$_2$ cooling. The supernovae evolve along two evolutionary paths according to whether they explode in \ion{H}{2} regions or neutral halos. Those in \ion{H}{2} regions first expand adiabatically and then radiate strongly upon collision with baryons ejected from the halo during its photoevaporation by the progenitor. Explosions in neutral halos promptly emit most of their kinetic energy as x-rays, but retain enough momentum to seriously disrupt the halo. We find that the least energetic of the supernovae are capable of destroying halos $\lesssim$ 10$^7$ $\Ms$, while a single PISN can destroy even more massive halos. Blasts in \ion{H}{2} regions disperse heavy elements into the IGM, but neutral halos confine the explosion and its metals. In \ion{H}{2} regions, a prompt second generation of stars may form in the remnant at radii of 100 - 200 pc in the halo. Explosions confined by large halos instead recollapse, with infall rates in excess of 10$^{-2}$ $\Ms$ yr$^{-1}$ that heavily contaminate their interior. This fallback may either fuel massive black hole growth at very high redshifts or create the first globular cluster with a radius of 10 - 20 pc at the center of the halo. Our findings allow the possibility that the first primitive galaxies formed sooner, with greater numbers of stars and distinct chemical abundance patterns, than in current models.