Can you actually see in real-time the
motion of this sound?

I don't think so. The evidence that it's a
sound wave seems to be the geometry of the pattern itself.

Since there's no long-term observations to determine actual velocity of
the waves, the question remains open as to whether they're 'gravity
waves' propagating at c or sound waves in interstellar gas.

IF they are GWs, their chaotic pattern suggests a violent event in the
object's past. Possibly the merger of a binary BH pair and subsequent
ringdown to the now-quiescent state. oc

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