Gamma Ray Bursts: basic facts and ideas

TL;DR

This paper reviews recent advances in understanding Gamma Ray Bursts, highlighting unresolved questions about their emission mechanisms, early afterglow phenomenology, and the implications of GeV emission detection by the Fermi satellite.

Contribution

It summarizes current knowledge and emphasizes the need for further research into GRB radiation mechanisms and early afterglow phenomena, especially with new observational data.

Findings

Detection of GeV emission from ~10% of GRBs by Fermi

Early afterglow phases show unexpected phenomenology

Uncertain radiation mechanisms for prompt emission

Abstract

The recent years witnessed a dramatic improvement in our knowledge of the phenomenology and physics of Gamma Ray Bursts (GRBs). However, our "pillars of knowledge" remain a few, while many aspects remain obscure and not understood. There is no general agreement on the radiation mechanism of the prompt emission, nor on the process able to convert the bulk motion of the fireball into random energy of the emitting leptons. The afterglow phase can now be studied at very early phases, showing an unforeseen phenomenology, still to be understood. In this context, the detection of ~GeV emission from ~10 per cent of GRBs, made possible by the {\it Fermi} satellite, can hopefully shed light on some controversial issues.