The differences between black holes and neutron stars are almost indistinguishable. Observed neutron stars are said to be 1.4 -2.1 solar masses ,the scientific community thought the same about black holes until we realised that there were supermassive black holes at the centre of certain galaxies.What if these are supermassive neutron stars instead ? .Gravitational and magnetic forces at the centre of a galaxy could cause conditions for their enormous size until critical mass which causes it to be annihilated along magnetic poles and then the whole thing starts again.The neutron star would be almost undetectable as gravity keeps the emissions from escaping .If light cannot escape a black hole how can extreme amounts of gamma radiation be jettisoned from the centre of it? There must be hidden mass ,dark matter ? maybe , neutrons ,definitely.