Background

The IDAnalyticBH thorn exists as a central location to place any initial dataset for black hole evolution that can be specified analytically in terms of the metric, $g_{ab}$, and extrinsic curvature, $K_{ab}$.

The thorn extends the admbase::initial_data parameter by adding the following datasets:

schwarzschild

Schwarzschild, in isotropic coordinates;

kerr

Kerr, in Boyer-Lindquist coordinates;

misner_bh

2 Misner black holes;

multiple_misner_bh

$N \ge 2$ Misner black holes; (Alas this code is currently broken; see the level 1 CCTK_VWarn() warning in src/Misner_points.c, function Misner_init().)

bl_bh

Multiple Brill-Lindquist black holes.

Initial data for lapse and shift can also be specified in this thorn.

The Cactus grid-functions corresponding to the initial data are inherited from the thorn CactusEinstein/ADMBase, along with the conformal factor grid-function, psi from CactusEinstein/StaticConformal, and its derivatives which are optionally set based on the value of the parameters admbase::metric_type and staticconformal::conformal_storage.

The IDAnalyticBH has been written and augmented over an number of years by many Cactus authors. These include John Baker, Steve Brandt, Carsten Gundlach, Joan Masso, Ed Seidel, Jonathan Thornburg, and Paul Walker. The following sections describe each of the initial datasets and their associated parameters in turn.