(ORDO NEWS) — Astronomers have discovered two large, mysterious objects erupting from the brightest black hole in the known universe.
Supermassive black hole 3C 273, found while studying cosmic radio waves in 1959, is a quasar, short for “quasi-stellar object” because the light emitted by these giants is bright enough to be mistaken for starlight.
Although black holes themselves do not emit light, the largest of them are surrounded by giant swirls of gas called accretion disks; as gas falls into the black hole at near-light speed, the friction heats up the disk and causes it to flare with radiation normally found in the form of radio waves.
Quasar 3C 273 is the first identified quasar. It is also the brightest, shining more than 4 trillion times as bright as Earth‘s Sun, while being more than 2.4 billion light-years away.
For decades, scientists have carefully studied the flaming core of a black hole, but because the quasar is so bright, studying the surrounding galaxy in which it resides has been almost impossible. This remarkable brightness has, ironically, left scientists largely in the dark about how quasars affect their host galaxies.
Strange radio structures
In the course of the work, the research team calibrated the ALMA radio telescope in Chile to separate the bright glow of the 3C 273 quasar from the light emitted by its host galaxy.
In the end, only the radio waves emitted by the quasar galaxy remained, which made it possible to detect two massive and mysterious radio structures that had not been seen before.
One structure appears to be a huge patch of radio emission that envelops the entire galaxy and then extends tens of thousands of light-years to the southwest.
This radio fog is overlaid by a second structure, a gigantic jet of energy known as the astrophysical jet, which also extends tens of thousands of light-years.
Scientists are not entirely sure how and why astrophysical jets form. However, they do know that jets are commonly seen around quasars and other supermassive black holes, and likely result from interactions between a black hole and its dusty accretion disk. Jets are usually made up of ionized (electrically charged) matter and travel at close to the speed of light.
The radiation emitted by these jets may appear brighter or dimmer depending on the radio frequency at which they are viewed, but the large radio structure surrounding the galaxy 3C 273 showed the same brightness regardless of its frequency.
According to the researchers, this suggests that the two radio structures were created by separate, unrelated phenomena.
What could it be?
After testing several theories, the team concluded that the large “radio fog” around the galaxy is due to star-forming hydrogen gas, which is ionized directly by the quasar itself. According to the researchers, this is the first time that ionized gas extends tens of thousands of light-years around a supermassive black hole.
The discovery touches on a longstanding conundrum in astronomy: Can a quasar ionize so much gas in its host galaxy that it prevents new stars from forming? To answer this question, the researchers compared the estimated mass of the galaxy’s gas to other galaxies of the same type and size.
It turned out that although the quasar had ionized a truly staggering amount of gas, rendering it useless for creating new stars, star formation in the galaxy as a whole was clearly not suppressed. This suggests that thriving, growing galaxies could still exist with radiation-emitting quasars at their centers.
“By applying the same technique to other quasars, we hope to understand how a galaxy evolves through interaction with the central core,” the scientists write in their paper.
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