How Quasars and Supermassive Black Holes Shaped the Early Universe

Astronomers have taken a look back at the young universe to learn a bit more about quasars and how they helped form and shape the evolution of galaxies. The findings could tell scientists a bit more about how quasars and their supermassive black holes helped form the universe.

In this case, the astronomers looked back nearly 13 billion years, which is when the universe was less than 10 percent of its present age. They used a combination of data gathered from powerful radio telescopes and supercomputer simulations.

Quasars themselves are among the most luminous objects in the universe, and the most distant quasars are so far away that when astronomers focus on them, they can actually peer back billions of years in time. Quasars themselves are powered by supermassive black holes at the center of galaxies, surrounded by a rapidly spinning disk-like region of gas. As the black hole pulls in matter from its surroundings, huge amounts of energy are released.

In this case, the scientists found that a quasar spits out cold gas of speeds of up to 2,000 kilometers per second, and across distances of nearly 200,000 light-years. How this cold gas, which is the raw material for star formation, can accelerate to such high speeds has long remained a mystery. Detailed comparisons revealed that the gas is first heated to temperatures of tens of millions of degrees by the energy released by the supermassive black hole powering the quasar. This enormous build-up of pressure accelerates the hot gas and pushes it to the outskirts of the galaxy.

The supercomputer simulations also showed that on its way out of the parent galaxy, there is just enough time for some of the hot gas to cool to temperatures low enough to be observable with radio telescopes.

"We found that while gas is launched out of the quasar at very high temperatures, there is enough time for some of it to cool through radiative cooling-similar to how the Earth cools down on a cloudless night," said Tiago Costa, lead author of the second paper detailing the findings, in a news release. "The amazing thing is that in this distant galaxy in the young universe the conditions are just right for enough of the fast moving hot gas to cool to the low temperatures that Claudia and her team have found."

The findings reveal a bit more about how quasars function. This, in turn, tells a bit more about star formation and, in turn, galaxy formation in the universe.

The findings are published in two papers found in the journals Monthly Notices of the Royal Astronomical Society and Astronomy & Astrophysics.

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