Extreme astrophysics at Lund Observatory
Extreme astrophysics concerns the formation and evolution of black holes and neutron stars. Neutron stars and stellar-mass black holes are formed when massive stars explode as supernovae. If a massive star is spinning rapidly, a ring of dense gas forms around the black hole or neutron star which may lead to a gamma-ray burst, which are the most energetic explosive events known. If two compact objects are formed in a tight binary, they will spiral together and merge as they lose angular momentum whilst emitting gravitational radiation. These mergers may also be the source of some of the observed gamma-ray bursts.
High-speed astrophysics explores the possible very rapid variability in processes near compact objects and in situations far from thermodynamic equilibrium. Events may occur over scales of kilometres or less, and there is no immediate hope for their spatial imaging. Insights can instead be gained through studies of their small-scale instabilities, on timescales of seconds, milli-, or microseconds, with a goal of eventually identifying quantum-optical effects on nanosecond timescales.