The effect of a merger of supermassive black holes

[Hornbein]

TL;DR Summary

What would be the effect of a merger of supermassive black holes?

What would be the effects of a merger of supermassive black holes? Such releases by far the greatest amount of energy of any event in our Universe as gravitational waves.

I suppose that a great deal of EM radiation is released, but I'm more interested in the gravitational waves. The resulting black hole may be accellerated so that it exits the galaxy at considerable velocity. But I'm mostly interested in the effect on nearby heavenly bodies. Such would have little effect on small objects but stars and planets would be fair game. I wonder whether a star or planet with resonant frequency close to that of the g waves would be destroyed, and if so at what range.

 

[collinsmark]

Summary: What would be the effect of a merger of supermassive black holes?

What would be the effects of a merger of supermassive black holes? Such releases by far the greatest amount of energy of any event in our Universe as gravitational waves.

I suppose that a great deal of EM radiation is released, but I'm more interested in the gravitational waves. The resulting black hole may be accellerated so that it exits the galaxy at considerable velocity.

Regarding the two supermassive black holes themselves, neither would be ejected anywhere. Before the merger, they would be rotating around their common barycenter, and after the merger, the resulting merged (and larger) supermassive black hole would remain at that common barycenter.

That said, any nearby, gravitationally locked bodies (stars, planets, etc) could -- but not necessarily would -- get slingshotted out of the region, as part of the process of the merger.

But I'm mostly interested in the effect on nearby heavenly bodies. Such would have little effect on small objects but stars and planets would be fair game. I wonder whether a star or planet with resonant frequency close to that of the g waves would be destroyed, and if so at what range.

I'll leave this for others to comment on. But I'm pretty confident that nearby stars and planets would not be destroyed (assuming they are not so close to be a part of the accretion disks), and I speculate that it wouldn't even be very dramatic.

 

[Hornbein]

Merger of supermassive black holes is non-Newtonian. The resulting hole may be ejected from a galaxy at considerable speed, as so much energy has gone out in the opposite direction via gravity waves.

https://academic.oup.com/mnrasl/article/366/1/L22/1050183
https://ui.adsabs.harvard.edu/abs/2008ApJ...678..780G/abstract