  Gamma-ray bursts (GRBs) are a mixed class of sources consisting of, at least,
the long duration and short-hard subclasses, the X-ray flashes, and the
low-luminosity GRBs. In all cases, the release of enormous amounts of energy on
a short timescale makes an energetic, relativistic or mildly relativistic
fireball that expands until it reaches a coasting Lorentz factor determined by
the amount of baryons mixed into the fireball. Radiation is produced when the
blast wave interacts with the surrounding medium at an external shock, or when
shell collisions dissipate kinetic energy at internal shocks. This series of
notes is organized as follows: (1) The observational situation of GRBs is
summarized; (2) Progenitor models of GRBs are described; (3) An overview of the
the blast-wave physics used to model leptonic emissions is given; (4) GRB
physics is applied to hadronic acceleration and ultra-high energy cosmic ray
production; (5) Prospects for GRB physics and gamma-ray astronomy with the
Fermi Gamma-ray Space Telescope (FGST, formerly GLAST), and space-based and
ground-based observatories are considered. Also included are exercises and
problems.

Astrophysics