What do we know about gamma-ray bursts?

Abstract

Decades of improving data and extensive theoretical research have led to a popular model of gamma-ray bursts. According to this model, a catastrophic event in a stellar system results in the formation of a compact central engine, which releases a fraction of a solar rest-mass energy within seconds in the form of ultra-relativistic jets. Dissipation of the jets energy leads first to prompt gamma-ray emission and later to a long lasting afterglow. Here I summarize the introduction that I gave to the debate "where do we stand?" in the conference "The Shocking Universe" held in Venice. This is a very brief summary of my view of the facts that we are (almost) certain about, models that are popular but may need rethinking, and main open questions.

proceedings of the The Shocking Universe meeting, Venice, September 2009