Abstrakt
The Schwarzschild metric, describing a static source, belongs to the class of so-called AI-metrics (in the classification of Ehlers and Kundt). The class of B-metrics can be formally obtained from the A-metrics via transformation using a complex unit.
In 1974, J. R.
Gott demonstrated that the BI-metric can be interpreted as describing a tachyonic source moving at superluminal velocity along a spacelike trajectory in flat space. We now generalize this interpretation to any value of a cosmological constant.
Specifically, we interpret the BI-metric with the cosmological constant as an exact gravitational field of a tachyon moving in the (anti-)de Sitter universe. This is a natural counterpart of the static Schwarzschild-(anti-)de Sitter AI-metric.