Is There a Way to Send Messages to Alien Observers?

Depending on where you are in the universe, you may see something a lot sooner than somebody else. It could be that there's something amazing that happened in the universe and the light from it is still getting here, but it's already hit alien astronomers. Photons from the event will arrive here before their paper on it arrives here. So we'll have a narrow window to claim that we came up with the ideas ourselves.