Gravity wave and model-independent axion

Understand

In this short comment, we notice that the model-independent axion contribution to the graviton mass at just outside the Schwarzschild radius is completely negligible in GW150914.

• The model-independent axion contribution to the graviton mass at the order $10^{-22}\,$eV might be possible for merger of black holes of mass of order $2\times 10^{14}\,$kg.