Supernovae and Gamma-Ray Bursts

Supernovae are explosions of stars which are triggered either by the implosion of the core of a star or a thermonuclear runaway, causing a bright optical display lasting for weeks to years. This chapter first explains the main explosion types, how they are classified and the principles that determine their lightcurves. It then discusses in more detail some of the most important supernova types, specifically SN 1987A, the last naked-eye supernova near our own Galaxy, Type Ia supernovae that have been used as standardizable cosmological distance candles, and gamma-ray bursts and their related supernovae. Special emphasis is given to the link of the various supernova types to their progenitor systems and a discussion of any outstanding issues. Causes for the large diversity of supernova types and sub-types are then systematically explored: these include binarity, the explosion mechanisms, rotation, metallicity and dynamical effects. Finally, some of the major topics of current interest are briefly discussed.