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Thanks to emissions powered by monster black holes, galaxies called
blazars rank among the most luminous objects in the universe.
They're also the most common sources of high-energy light seen by NASA's
Fermi Gamma-ray Space Telescope.
Like all active galaxies, a blazar gets its energy from matter
falling toward a central supermassive black hole.
A small part of this material forms particle jets that travel outward in
opposite directions at near the speed of light. What makes blazars so
intense is that we happen to be looking almost directly down the jet.
Now, Fermi team members have identified five
of the most distant gamma-ray blazars known.
The record holder emitted its light when the universe was just one-tenth its current age.
That object hosts a black hole with a mass of about 
3 billion suns. That's 750 times bigger than 
the black hole at the heart of our own galaxy. Another of these distant
blazars boasts a black hole more than twice this size.
In fact, the observed properties of all five of these blazars
show they're the most extreme known members of this extreme
galaxy class. The discovery makes it clear that
enormous black holes formed very early in cosmic history,
but astronomers aren't sure how. In general it's thought that
large galaxies--and their black holes--were built up over time through a
series of mergers with other smaller galaxies.
It is unknown exactly how mergers can build a 
billion-solar-mass black hole before the universe is much more than 
one billion years old. But after netting five of these extreme blazars,
researchers hope to find more of them in Fermi data.
These objects allow scientists to map out how the most powerful jets in the universe
evolved over cosmic time scales. And scientists hope
that additional examples will help them better understand
how supermassive black holes developed so rapidly in the early universe.
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