>> So one could say that there's a low prior for such a system to exist. I have no other knowledge, but just from the information in your comment, can we test

>> So one could say that there's a low prior for such a system to exist. I have no other knowledge, but just from the information in your comment, can we test the low prior assumption? Would this bh still have been identifiable as the most massive known, if it did not have both of the following characteristics? - blazar, pointed directly at us (makes it noticeable) - binary, (makes it measurable at such a massive scale)