Long-Term Evolution of Collapsar: Mechanism of Outflow Production

TL;DR

This study uses advanced 2D hydrodynamic and magnetohydrodynamic simulations to explore how slowly rotating massive star collapses produce jets and outflows, shedding light on long-term collapsar evolution relevant to gamma-ray bursts.

Contribution

It provides the first detailed long-term simulations of low angular momentum collapsars, revealing jet formation mechanisms via MHD and neutrino processes.

Findings

Jets can be launched by both MHD and neutrino processes.

Outflows may evolve into gamma-ray bursts or remain weak.

Long-term evolution up to 10 seconds was successfully simulated.

Abstract

We present our numerical results of two-dimensional hydrodynamic (HD) simulations and magnetohydrodynamic (MHD) simulations of the collapse of rotating massive stars in light of the collapsar model of gamma-ray bursts (GRBs). Pushed by recent evolution calculations of GRB progenitors, we focus on lower angular momentum of the central core than the ones taken mostly in previous studies. By performing special relativistic simulations including both realistic equation of state and neutrino cooling, we follow a long-term evolution of the slowly rotating collapsars up to 10 s, accompanied by the formation of jets and accretion disks. We find such outfows can be launched both by MHD process and neutrino process. We investigeate the properties of these jets whether it can become GRBs or remains primary weak outflow.