Four quasars have been found together within a nebula in an extremely rare gathering that is puzzling astronomers. This rare quasar quartet is the first of its kind ever seen anywhere in the Universe.
Quasars are highly energetic bodies, driven by the massive gravitational fields of active black holes. These objects are young galaxies still developing into more familiar forms. The massive output of energy is driven by vast amounts of matter falling into a super-massive black hole. For a time, these quasars can outshine the combined output of hundreds of billions of stars in their home galaxies.
Because the lifetime of a quasar is so short compared with that of a galaxy, they are nearly always seen far apart from one another. Quasars are occasionally seen in pairs, but never before in a pack including four of the bodies. Researchers estimate the chances of seeing such a collection at just one in 10 million. Astronomers discovering the four quasars within the cloud of gas and dust dubbed the encompassing feature the "Jackpot Nebula." This feature glows from light released by the highly energetic quasars contained within the body.
The bundle of quasars is surrounded by a dense cloud of gas reaching one million light years from one side to another. This structure, one of the most massive structures seen in the far reaches of the Universe, sits 10 billion light years from Earth, and astronomers today see the object as it was just a few billion years after the Big Bang.
The region of the Universe where this conglomeration is located is rich in matter, containing several hundred times as many galaxies as most regions of space seen at a similar distance.
Galaxies today exist mostly in galaxy clusters. The four quasars close together in a cloud of cool, dense gas could help explain how these clusters may have formed. It could also help explain how quasars themselves are triggered — some astronomers believe they are "set ablaze" by gas during collisions between young galaxies. These types of encounters would be more common in regions of the Universe where galaxies were more plentiful.
"The giant emission nebula is an important piece of the puzzle, since it signifies a tremendous amount of dense cool gas," said Fabrizio Arrigoni-Battaia, a doctoral student at the Max Planck Institute for Astronomy.
Super computer models suggest massive objects in the early Universe should be filled with hot, thin gas clouds — the opposite of what astronomers found. This new discovery could force astrophysicists to rethink theories on the evolution of quasars, the most energetic bodies in the Universe, as well as the largest — clusters of galaxies.
