For only the second time in history, a team of scientists have discovered an extremely rare triple quasar system. Quasars
are extremely bright and powerful sources of energy that sit in the
center of a galaxy, surrounding a black hole. In systems with multiple
quasars, the bodies are held together by gravity and are believed to be
the product of galaxies colliding.
Astronomers find it very difficult to observe triplet quasar systems,
because of observational limits that prevent researchers from
differentiating multiple nearby bodies from one another at astronomical
distances. Moreover, such phenomena are presumed to be very rare. By
combining multiple telescope observations and advanced modeling, the
team—led by Emanuele Farina of the University of Insubria in Como Italy—was able to find the triplet quasar, called QQQ J1519+0627.
The light from the quasars has traveled 9 billion light years to
reach us, which means the light was emitted when the universe was only a
third of its current age. Advanced analysis confirmed that what the
team found was indeed three distinct sources of quasar energy and that
the phenomenon is extremely rare. Two members of the triplet are closer
to each other than the third. This means that the system could have been
formed by interaction between the two adjacent quasars, but was
probably not triggered by interaction with the more-distant third
quasar.
Furthermore, no evidence was seen of any ultra-luminous infrared galaxies,
which is where quasars are commonly found. As a result, the team
proposes that this triplet quasar system is part of some larger
structure that is still undergoing formation.
"Honing our observational and modeling skills and finding this rare
stellar phenomenon will help us understand how cosmic structures
assemble in our universe and the basic processes by which massive
galaxies form," said Carnegie's Michele Fumagalli."Further study will
help us figure out exactly how these quasars came to be and how rare
their formation is," Farina added.
For more information: The new work appears in "Caught in the Act:
Discovery of a Physical Quasar Triplet", E. P. Farina, C. Montuori, R.
Decarli and M. Fumagalli, Monthly Notices of the Royal Astronomical Society,
in press. A preprint of the paper can be downloaded from
arxiv.org/abs/1302.0849 Journal reference: Monthly Notices of the Royal
Astronomical Society.
The x-ray image at the top of the page shows a typical Quasar, PKS
0637-752, one of the most powerful, continually emitting objects in the
universe. Powered by the accretion of matter onto a central,
supermassive black hole, in every band these objects far outshine the
giant elliptical galaxies that host them. Their activity takes many
forms, including a hot accretion disk and corona, a cooler, surrounding
torus, and emission line regions. About 10% of quasars exhibit powerful
jets (an example is shown in the figure at bottom left), which are
launched from the central engine at nearly the speed of light and
propagate out for hundreds of kiloparsecs, well outside the host galaxy
and out into the surrounding cluster that the galaxy resides in.
http://www.jca.umbc.edu/~perlman/jetphys_summer.html
Source: The Daily galaxy via Carnegie Institution for Science
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