Gamma-ray burst progenitors

TL;DR

This review synthesizes current knowledge on gamma-ray burst progenitors, combining observations, modeling, and analog systems to estimate formation scenarios and rates for long and short GRBs, and explores central engine models.

Contribution

It provides a comprehensive overview of progenitor scenarios for both long and short GRBs, integrating multiple lines of evidence and discussing unifying models for luminous transients.

Findings

Likely progenitors for long GRBs involve massive stars.

Compact object binaries are probable sources of short GRBs.

Central engine models may unify various luminous transient phenomena.

Abstract

We review our current understanding of the progenitors of both long and short duration gamma-ray bursts (GRBs). Constraints can be derived from multiple directions, and we use three distinct strands; i) direct observations of GRBs and their host galaxies, ii) parameters derived from modeling, both via population synthesis and direct numerical simulation and iii) our understanding of plausible analog progenitor systems observed in the local Universe. From these joint constraints, we describe the likely routes that can drive massive stars to the creation of long GRBs, and our best estimates of the scenarios that can create compact object binaries which will ultimately form short GRBs, as well as the associated rates of both long and short GRBs. We further discuss how different the progenitors may be in the case of black hole engine or millisecond-magnetar models for the production of GRBs, and how central engines may provide a unifying theme between many classes of extremely luminous transient, from luminous and super-luminous supernovae to long and short GRBs.