<< Agreement between the postinspiral measurements of mass and spin and those using the full waveform supports the hypothesis that the GW150914 merger produced a Kerr black hole, as predicted by general relativity, and provides a test of the no-hair theorem at the ∼10% level. An independent measurement of the frequency of the first overtone yields agreement with the no-hair hypothesis at the ∼20% level. >>
Maximiliano Isi, Matthew Giesler, et al. Testing the No-Hair Theorem with GW150914. Phys. Rev. Lett. 123, 111102. Sep 12, 2019. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.111102
Synopsis: Hunting for Hair on Coalescing Black Holes. A fresh look at data from the first detected black-hole merger supports the “no hair” theorem. Sep 12, 2019. https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.111102
'No-hair' theorem https://en.m.wikipedia.org/wiki/No-hair_theorem
Kerr black hole https://en.m.wikipedia.org/wiki/Rotating_black_hole
