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Black Holes Encyclopedia

ULAS J1120-0641

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In the constellation Leo


13 billion light-years (4 gigaparsecs)


2 billion times the mass of the Sun


Larger than the diameter of Neptune's orbit around the Sun

Discovery Methods


ULAS J1120-0641

A quasar near the edge of the observable universe is shedding some light on how supermassive black holes are born.

ULAS J1120-0641 was discovered in an infrared sky survey in 2010. Astronomers then used the Gemini North telescope and the Very Large Telescope to study the system in detail. They found that we are seeing the system as it looked 13 billion years ago, less than 800 million years after the Big Bang.

From its distance, astronomers computed the system's luminosity, the measure of its total energy output, at roughly 63 trillion times the brightness of the Sun, or a thousand times the brightness of the entire Milky Way galaxy.

The system is so bright because vast amounts of gas are spiraling into a black hole that is roughly 2 billion times as massive as the Sun — the largest black hole yet detected at such distances. The gas is heated to billions of degrees so it emits enormous amounts of energy, even though the gas disk is probably only a few times larger than our solar system.

The quasar may be in the core of a protogalaxy, in which giant clouds of gas are collapsing to give birth to stars. Alternatively, it may be embedded in a thick cloud of hydrogen gas that has not yet started to give birth to a galaxy.

Either way, it was a bit of a surprise to find a black hole that massive so soon after the Big Bang. The discovery shows that supermassive black holes can form quickly, which will help astronomers understand the process that gave birth to them.

It also will help them understand the relationship between the birth of a galaxy and the birth of its central black hole. Current theories suggest the black hole first helps give birth to new stars (as it pulls in gas) then later shuts down the starbirth process (as radiation from the disk around the black hole blows away the remaining gas).

The astronomers who discovered ULAS J1120 suggest there could be up to 100 more quasars at similar distances with similar supermassive black holes. Discovering these systems would help shed even more light on galaxies and supermassive black holes in the early universe.



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This document was last modified: May 13, 2013.


ULAS J1120-0641
Artist's Rendering


ULAS J1120-0641
Zooming in on the quasar.