A team of astronomers has discovered the first quadruple quasar
The quartet resides in one of the most massive structures ever discovered in the distant universe and is surrounded by a giant nebula of cool dense gas. Because the discovery comes with one-in-ten-million odds, perhaps cosmologists need to rethink their models of quasar evolution and the formation of the most massive cosmic structures.
The four quasars are surrounded by a giant nebula of cool dense hydrogen gas, which emits light because it is irradiated by the intense glare of the quasars. In addition, both the quartet and the surrounding nebula reside in a rare corner of the universe with a surprisingly large amount of matter.
Principal investigator J. Xavier Prochaska of the University of California Santa Cruz said that there are several hundred times more galaxies in this region than one would expect to see at these distances.
Given the exceptionally large number of galaxies, this system resembles the massive agglomerations of galaxies, known as galaxy clusters that astronomers observe in the present-day universe, but because the light from this cosmic metropolis has been travelling for 10 billion years before reaching Earth, the images show the region as it was 10 billion years ago, less than 4 billion years after the big bang. It is thus an example of a progenitor or ancestor of a present-day galaxy cluster, or proto-cluster for short.
Piecing all of these anomalies together, the researchers tried to understand what appears to be their incredible stroke of luck. If you discover something which, according to current scientific wisdom should be extremely improbable, you can come to one of two conclusions: either you just got very lucky, or you need to modify your theory, lead researcher Joseph Hennawi said.
The study is published in the journal Science.
