So thirsty are theorists for new insights into black holes and relativistic processes that, with each LIGO detection, observational astronomers have leapt into action to target those enormous patches
of sky, hoping to see some afterglow or other emission
of electromagnetic radiation — even though by definition the
resulting larger black hole should emit no light.
They say that the
electromagnetic radiation, which took the form
of γ - rays and seemed to exceed what known sources should produce, could be the
result of dark - matter particles concentrating near the centre
of the Milky Way and then colliding with and annihilating each other.