In a groundbreaking discovery, scientists have now determined the precise size of the swirling ring around a supermassive black hole. This unexpected revelation holds the potential to enhance our understanding of how these enormous cosmic entities grow and how the galaxies nearby change as time goes on.
Swirling rings around black holes
Accretion disks are colossal swirling rings of super-hot gas, dust, and plasma that spin around black holes or other massive objects in space, like pulsars. These disks around black holes are formed from the leftovers of destroyed stars, exoplanets, and other material that got torn apart as it got pulled closer to the event horizon.
The event horizon is the point where nothing, not even light, can escape from the black hole’s super-strong gravity.
As these accretion disks whirl around, they give off various types of electromagnetic radiation, such as X-rays, infrared rays, radio waves, and visible light. This radiation is crucial because it’s the only part of a black hole that astronomers can actually observe and study.
Visualizing the accretion disks
Accretion disks are easiest to see when we use infrared light. When these swirling masses spin around, they give off something called a “double-peak.” It’s like two energy spikes caused by excited hydrogen gas.
These spikes come from both sides of the accretion disk. There is the part that’s spinning away from us and the part that’s spinning toward us.
The double peaks come from the edge of the accretion disk that’s closest to the event horizon. This is the point where nothing can escape the black hole’s gravity. They can tell us where the spinning disks begin but not where they end.
Newly discovered double peaks
In a recent study published in The Astrophysical Journal Letters, scientists made an interesting discovery. They found a second set of double peaks on the outer edge of an accretion disk encircling a supermassive black hole known as III Zw 002.
This black hole is quite far from us, over 22 million light-years away, and it’s incredibly huge, at least 400 million times the mass of our sun.
By looking at these two pairs of double-peaks, the researchers figured out that the accretion disk around III Zw 002 has a radius of about 52.4 light-days. To put that in perspective, it’s more than nine thousand times the distance from Earth to the sun.
The scientists weren’t actually trying to find that second set of double-peaks around III Zw 002. Their original goal was to gather data to make sure the accretion disk, which was initially spotted in 2003, was really there.
Results obtained from GNIRS
To gather this novel information, researchers used a tool called the Gemini Near-Infrared Spectrograph (GNIRS), which is part of the Gemini North telescope in Hawaii.
What’s special about GNIRS is that it can measure a broader range of wavelengths than regular infrared light. It can also pick up emissions in different wavelengths all at once. This cool feature helped the team spot that second set of double-peaks.
At first, the researchers couldn’t believe their eyes. They went over the data multiple times, thinking it might be a mistake. But each time, they got the same exciting result.
As galaxies create matter/antimatter jets while they turn slowly during black hole accretion, they are, indeed, slowly creating new accretion disks, perpendicular to the orig. plane, this way forming new galaxies with new matter, new stars and planetary disks are formed eternally pic.twitter.com/XG7KJ9RZbD
— The Unforgettable (@Mr_Spock_007) September 3, 2023
As study co-author Alberto Rodríguez-Ardila, an astronomer at the Canary Islands Astrophysics Institute, put it, “We reduced the data many times thinking it could be a mistake, but every time we saw the same exciting result.”
The scientists think that this discovery could be really helpful in solving the puzzles about supermassive black holes.
Alberto Rodríguez-Ardila explained, “The detection of such double-peaked profiles puts firm constraints on the geometry of a region that is otherwise not possible to resolve.”
The research team plans to keep an eye on the accretion disk around III Zw 002 to see how it gets bigger as time goes on.
However, this year, scientists have made another big leap in understanding accretion disks. In May, they revealed that they managed to make artificial accretion disks using plasma in a lab, which was a first-ever achievement.
These imitation rings only stick around for a tiny fraction of a second, but they give us clues about how real accretion disks come into being.