The recent discovery of gravitational waves from the site of a merger of
two stellar mass black holes, may have been accompanied by a Gamma Ray
Burst event too! Why is this even news? Because the theory of black hole
mergers suggests that no form of light should be emitted, only energy in
the form of gravitational waves. If two neutron stars had merged into a
black hole, then sure, no problem there should be light emission, but
not from black holes. So possible new physics found?

Yousuf Khan

[1602.03920] Fermi GBM Observations of LIGO Gravitational Wave event
GW150914
http://arxiv.org/abs/1602.03920