Microlensing of long-duration gravitational wave signals originating from Galactic sources

Gravitational microlensing of gravitational waves (GWs) is a fascinating phenomenon that occurs when a massive object, such as a star or a black hole, passes between a distant GW source and an observer. This can lead to the magnification and distortion of the GW signal, providing valuable insights into both the lensing object and the GW source. This phenomenon is particularly interesting when considering long-duration GW signals originating from Galactic sources, such as continuous waves (CWs) emitted by e.g. rotating non-axisymmetric neutron stars. Temporal amplification patterns of these signals can be used to enhance the otherwise weak (sub-threshold) GW signals from such sources, and lead to their detection.

With Sudhagar Suyamprakasam, Sreekanth Harikumar, Paweł Ciecieląg, Przemysław Figura and Marek Biesiada we have explored various aspects of these phenomena, and presented examples of how the signal, an analog to the electromagnetic ‘‘Paczyński curve’’, may look like when analyzed by the time-domain F-statistic search pipeline, TDFstat; see arXiv:2503.21845 for details.