For decades, scientists have been on the hunt for brilliant galaxies in the distant universe. These quasars were first noticed for being spectacularly bright – some of the most energetic objects ever discovered. But astronomers think many of them – in fact, the vast majority from the early universe – may be in hiding, camouflaged behind much closer galaxies.
Because of their brightness, astronomers want to use quasars to probe the era of reionization. This is a time less than a billion years after the Big Bang, when the first generation of stars and then galaxies formed. Quasars are supermassive black holes in the centers of galaxies, actively gobbling material. They’re some of the few objects that can be seen from such a distance, which makes them some of the only glimpses we have of the early universe.
Often even quasars are often too dim to see from so long ...
