Could be a tidal lock of a pulsar around a black hole. We only get the milisecond because the black hole is obscuring the burst pointing to us. Otherwise the be

Could be a tidal lock of a pulsar around a black hole. We only get the milisecond because the black hole is obscuring the burst pointing to us. Otherwise the beam is not pointed at us. (P)--->---- ( BH ) ----> ( Solar System )