It’s triplets for the Carnegie Institution for Science’s Michele Fumagalli and her team who have discovered an extremely unusual trio of quasars, some 9 billion light years away, locked in a system knitted together by the force of gravity.
Quasi-stellar radio sources, or quasars as they are most commonly known, are distant memories of the Universe’s early history. While they might be extremely distant, they are outstandingly bright, powered by active supermassive black holes that are feeding hungrily off a disc of gas sitting, hugging the centres of massive galaxies. Quasars may form in one of two ways: as the product of a violent smash-up between two galaxies, or as the target for infalling clouds of intergalactic gas.
The exotic find, dubbed QQQ J1519+0627, is thought to have formed when two adjacent galaxies began to interact with one another, igniting their quasar activity. They were then joined by a third quasar that approached the duo.
“Each quasar is associated to a massive black hole hole in the centre of a galaxy,” Fumagalli tells All About Space. “These three quasars therefore inhabit three massive galaxies that happen to be in close proximity, in the early stage of a collision, that will potentially form a very massive galaxy.”
Fumagalli admits that quasars themselves are rare and finding three in the same area of sky, particularly when it is very difficult to observe triplet quasar systems, has astounded the researchers but will hopefully help us to understand how cosmic structures in our Universe assemble as well as the processes in which massive galaxies form. Speaking of the difficulty in observational limits, Fumagalli says: “Looking at the sky, we can see the Moon, the Sun and other planets around the Sun. But if we look a few astronomical units further away, we can only see stars, and not the planets around them. Similarly, we cannot easily see the stars in other galaxies, and can not even resolve individual galaxies at cosmological distances.”
However, using combined observations from the New Technology Telescope of the European Southern Observatory at La Silla, Chile as well as from the Calar Alto Observatory in Spain, the team were able to overcome the obstacle. Shining with a light emitted when the Universe was only a third of its age, the trinity of quasars were revealed.
Now with the bit between their teeth, the researchers, led by Emanuele Farina of the University of Insubria in Como, Italy, intend to probe the quasars for answers.
“We are now trying to obtain high resolution images of this system, either with the Hubble Space Telescope or adaptive optics,” explains Fumagalli. “This will allow us to identify the optical light form the galaxies which host these quasars, and to study the way they interact.”
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Image courtesy of ESO/M. Kornmesser