Black hole merger - what would happen if ..

[WACG]

Would there be any observable difference between these two cases: A) two "ordinary" black holes merge. B) one of the two merging black holes is derived from anti-matter? Thanks for any thoughts.

[Dmitry67]

There should be no difference.
1. Black holes do not have 'solid surface'
2. When any matter approaches singularity inside the horizon, it becomes a subject of so heavy tidal forces/hawking emission from apparent horizons/heating that the difference between matter and antimatter dissapears (like it was at some point of history soon after the Big bang)

[Jonathan Scott]

Would there be any observable difference between these two cases: A) two "ordinary" black holes merge. B) one of the two merging black holes is derived from anti-matter? Thanks for any thoughts.

According to the "no hair" theorem, the only externally observable properties of a standard classical black hole are mass (rest energy), electric charge and angular momentum, so there is no observable distinction between one made of matter and one made of antimatter.