Detecting the Beaming Effect of Gravitational Waves

Understand

The models currently used in the detection of gravitational waves (GWs) either do not consider a relative motion between the center-of-mass of the source and the observer, or usually only consider its effect on the frequencies of GWs.

• However, it is known for light waves that a relative motion not only changes the frequencies but also the brightness of the source, the latter of which is called the `beaming effect'.
• Here we investigate such an effect for GWs and find that the observed amplitude of a GW signal, unlike the behavior of light, is not a monotonic function of the relative velocity and responds differently to the two GW polarizations.
• We attribute the difference to a rotation of the wave-vector, as well as a reorientation of the GW polarizations.