Very interesting, Fred.

I cannot help thinking that while this is strong supporting data for the existence of gravitational waves (GWs), it is not quite evidence! In the preprint the authors do concede that there are other possible explanations for the observations. Apart from the ones they mention, I also think that the dynamics of coalescence of rapidly spinning black holes may cause recoils in other ways than by pure anisotropic emission of GWs. Maybe they are observing only one of the pair being ejected from the galaxy?

With that said, I do not doubt the existence of GWs, because I think the observed binary pulsars provide very strong evidence.

Regards,

Burt Jordaan (www.Relativity-4-Engineers.com)