An axisymmetric generalized harmonic evolution code

Understand

We describe the first axisymmetric numerical code based on the generalized harmonic formulation of the Einstein equations which is regular at the axis.

• We test the code by investigating gravitational collapse of distributions of complex scalar field in a Kaluza-Klein spacetime.
• One of the key issues of the harmonic formulation is the choice of the gauge source functions, and we conclude that a damped wave gauge is remarkably robust in this case.
• Our preliminary study indicates that evolution of regular initial data leads to formation both of black holes with spherical and cylindrical horizon topologies.