The First Supernova Explosions in the Universe

Volker Bromm,Lars Hernquist,Naoki Yoshida

doi:10.1086/379359

Abstract

We investigate the supernova explosions that end the lives of massive Population III stars in low-mass minihalos (M ~ 106 M☉) at redshifts z ~ 20. Employing the smoothed particle hydrodynamics method, we carry out numerical simulations in a cosmological setup of pair-instability supernovae with explosion energies of ESN = 1051 and 1053 ergs. Whereas the lower explosion energy leaves part of the halo intact, we find that the more energetic explosion leads to the complete disruption of the gas in the minihalo and expels 90% of the stellar metals into a region ~1 kpc across over a timescale of 3-5 Myr. Because of this burstlike initial star formation episode, a large fraction of the universe could have been endowed with a metallicity floor, Zmin 10-4 Z☉, already at z 15.

Highlights

One of the most important challenges in modern cosmology is to understand how the cosmic dark ages ended (e.g., Barkana & Loeb 2001; Bromm & Loeb 2003a)
If the star has a mass in the narrow interval 140 ∼< M∗ ∼< 260M⊙, it will explode as a pair-instability supernova (PISN), leading to the complete disruption of the progenitor (Fryer, Woosley, & Heger 2001; Heger et al 2003)
In this Letter, we present numerical simulations of the supernova explosions that end the lives of massive Pop III stars

Summary

INTRODUCTION

One of the most important challenges in modern cosmology is to understand how the cosmic dark ages ended (e.g., Barkana & Loeb 2001; Bromm & Loeb 2003a). In contrast to earlier work, both analytical (e.g., Larson 1974; Dekel & Silk 1986; Scannapieco, Ferrrara, & Madau 2002; Furlanetto & Loeb 2003) and numerical (e.g., Mori, Ferrara, & Madau 2002; Thacker, Scannapieco, & Davis 2002; Wada & Venkatesan 2003), we here focus on the minihalos that are the sites for the formation of the very first stars The gas in these halos, with masses of M ∼ 105 − 106M⊙ and virializing at z ∼> 20, can only form stars in the presence of a sufficient amount of H2, the only viable coolant in these systems (e.g., Haiman, Thoul, & Loeb 1996; Tegmark et al 1997; Yoshida et al 2003a). This transition redshift is an important ingredient in determining the reionization history of the universe, which has very recently been constrained by the WMAP satellite (e.g., Cen 2003; Ciardi, Ferrara, White 2003; Haiman & Holder 2003; Wyithe & Loeb 2003a,b; Sokasian et al 2003; Yoshida et al 2003b)

NUMERICAL METHODOLOGY

Initial Conditions and Clump Formation

Radiative Feedback

SIMULATIONS

SUMMARY AND CONCLUSIONS