Courbin, Meylan, Djorgovski, et al., EPFL/Caltech/WMKO

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Astronomers spot one-in-10-million phenomenon in early universe

Find one quasar—a rare, superbright galaxy core in deep space—and you’d think yourself pretty lucky. So a team of astronomers is wondering how it managed to find four closely spaced quasars all at once (pictured), a lucky break they calculate is a one-in-10-million chance. 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. The infalling material gets so hot that it shines hundreds of times brighter than the whole galaxy it is in. 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, as they report online today in Science. 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. But current numerical simulations of how galaxy clusters form suggest they should be in areas with much hotter and less dense gas. So is this a cosmic fluke, or is it time to rewrite our theories of how the universe’s largest structures form?