They're literally the sounds of space ringing, and they will travel out from these black holes at the speed of light as they ring down and coalesce to one spinning, quiet black hole at the end of the day.
Elas são, literalmente, os sons do espaço, e viajam para fora desses buracos negros à velocidade da luz à medida que soam e coalescem para um buraco negro giratório e calmo ao final do dia.