My alternative guess addition to neutron star merger:
Correlated LIGO mega noise peaks and the possible relation with gravity lighthouse effects of aligned micro sunspot black holes see:
https://bigbang-entanglement.blogspot.nl/2017/07/correlated-ligo-mega-noise-peaks-and.html
Also: temporaly observed at the Jupiter rings.
Second possibility: Splitting large black hole by relative small BH. see below: Spire/ Eagle nebula BH splittinginto two eaqual sized Herbig haro black holes for new star formation in between.
