A What does the image of the black hole say about general relativity?

haael
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We all heard about the "photo of black hole".

My question is: did this image show any hints of physics beyond general relativity?

I read once (not sure where) that the apparent size of black hole shadow is very sensitive to corrections to general relativity. Add some minor correction and the shadow gets much bigger / smaller.

Can we say that the "photo of black hole" is consistent with general relativity within current bounds?
 
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The main paper:
https://iopscience.iop.org/article/10.3847/2041-8213/ab0ec7/metasays this in the abstract:
"Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. "
 
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