Aren’t gravitational waves involved in all these super luminous events? I can’t think of one where they are not at least suspected of being involved.
Well, a supernova throws off a lot of mass, but gravitational waves require both mass and acceleration; it’s not enough if there is just a shift of mass. In a supernova, the mass ejected would be decelerating, unless there was some other nearby gravitational source to accelerate it, so I don’t think it could produce gravitational waves.