1.1 Current fields of research
Relativity is a necessary ingredient for describing astrophysical phenomena involving compact objects.
Among these phenomena are core collapse supernovae, X-ray binaries, pulsars, coalescing neutron
stars, formation of black holes, micro-quasars, active galactic nuclei, superluminal jets and
gamma-ray bursts. General relativistic effects must be considered when strong gravitational fields are
encountered as, for example, in the case of coalescing neutron stars or near black holes. The
significant gravitational wave signal produced by some of these phenomena can also only be
understood in the framework of the theory of general relativity. There are, however, astrophysical
phenomena which involve flows at relativistic speeds but no strong gravitational fields, and thus at
least certain aspects of these phenomena can be described within the framework of special
relativity.
Another field of research, where special relativistic “flows” are encountered, are heavy-ion collision
experiments performed with large particle accelerators. The heavy ions are accelerated up to
ultra-relativistic velocities to study various aspects of heavy ion collision physics (like, e.g., multi-particle
production, the occurrence of nuclear shock waves, collective flow phenomena, or dissipative processes), to
explore the equation of state for hot dense nuclear matter, and to find evidence for the existence of the
quark-gluon plasma.
