The gravitational wave strain in the characteristic formalism of numerical relativity

Understand

The extraction of the gravitational wave signal, within the context of a characteristic numerical evolution is revisited.

• A formula for the gravitational wave strain is developed and tested, and is made publicly available as part of the PITT code within the Einstein Toolkit.
• Using the new strain formula, we show that artificial non-linear drifts inherent in time integrated waveforms can be reduced for the case of a binary black hole merger configuration.
• For the test case of a rapidly spinning stellar core collapse model, however, we find that the drift must have different roots.