Pendorain, admiral of the illustrious Tenth Fleet, had gathered its fleet near the Xzlicyan Pulsar to nurse its wounds. Battle against the hated Andecklin was not going well. The fleet was using the intense, modulating magnetic fields of the pulsar to induct power for repairs. But navigation was offline and most of the sensors were down — so nobody knew when the EM stream from the pulsar swept past all the ships. Navigational shields absorbed the brunt of the stream (except for the destroyer Hendi, which was destroyed, which is what destroyers do, but not normally to themselves) and repairs continued....
Some 40 million years later, astronomer Zhāng Ai just happened to be looking at ULX-1 in NGC 5907 at the right time to see something amazing... a snapshot of what's obviously the first real evidence of artificial construction ever seen by Humanity.
Question: Can the EM stream from a pulsar (or similar astronomical coolness) be bright enough to create a "flash bulb" effect that, if we (miraculously) are looking at the right place at the right time, could illuminate a fleet of space ships that, in size and mass, are similar to a U.S. aircraft carrier group?
Please assume the reflectivity along the entire EM spectrum of an aircraft carrier. I'm not in a position to postulate what an advanced-tech alien fleet may or may not be able to do.
I understand that today's data-gathering abilities might not have the resolution to see a fleet, especially at the distance used in my backstory statement. But work with me on that one. It's only a matter of time. Otherwise, please assume real-life technology.