The many phases of gamma-ray burst afterglows

Gamma-ray bursts are the brightest sources in the universe. Their afterglows have been observed for about 15 years now, and their study has greatly advanced our understanding of these, mysterious until recently, events. In a way, gamma-ray bursts can be seen as huge cosmic bombs which convert gravitational energy to photons. Afterglow radiation is the result of the drastic effect that these explosions have on their environment. In this thesis the focus is on the different phases of this interaction and the transitional stages connecting them. The chapters of this book present theoretical models for the dynamics and spectra during the entire afterglow evolution, contributing towards a better interpretation of the accumulating observations by past, current and future telescopes.