Gamma Ray Burst Central Engines

TL;DR

This review discusses the theoretical models of long-duration gamma-ray burst central engines, comparing collapsar and proto-magnetar models based on key physical requirements and observational features.

Contribution

It provides a comparative analysis of collapsar and proto-magnetar models, highlighting the proto-magnetar's ability to produce high Lorentz factors and sustained luminosity.

Findings

Proto-magnetar model can produce Lorentz factor ~100.

Both models must meet angular momentum and duration requirements.

The models explain association with supernovae and flow asymmetry.

Abstract

I review aspects of the theory of long-duration gamma-ray burst (GRB) central engines. I focus on the requirements of any model; these include the angular momentum of the progenitor, the power, Lorentz factor, asymmetry, and duration of the flow, and both the association and the non-association with bright supernovae. I compare and contrast the collapsar and millisecond proto-magnetar models in light of these requirements. The ability of the latter model to produce a flow with Lorentz factor ~100 while simultaneously maintaining a kinetic luminosity of ~10^50 ergs/s for a timescale of ~10-100 s is emphasized.