Gravitational wave memory in conformally flat spacetimes

Understand

We study the gravitational wave memory effect in spacetimes related to flat space by a conformal transformation.

• The discussion is general but the gravitational wave length scale is assumed to be small compared with the background curvature radius.
• The general formulas are applied to Friedmann-Robertson-Walker metrics of all spatial curvatures.
• The effect of new terms stemming from spatial curvature is potentially detectable in future gravitational wave measurements.