Quasars are rare because they are a brief phase that all galaxies go through, when the supermassive black hole at their centers consumes matter at a high rate.
While carrying out a survey using the W. M. Keck telescope in Hawaii, the researchers found the quasar quartet embedded in a giant cloud of cool dense gas.
The quasars are in the middle of a particularly crowded part of the early universe, with a greater than average number of galaxies. The cloud of cool gas might also be providing food for the guzzling black holes. The quartet and its environs, snapped some 10 billion years ago, look like a galaxy cluster—a huge conglomeration of galaxies seen in the present-day universe—during its formative years.