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Mechanism discovered that creates the gas disks around black holes

Sometimes, the road to discovering the secrets of black holes and their disks isn’t a straight line. It’s a winding journey through the cosmos, involving years of rigorous research and cutting-edge technology.

Such is the case with a group of dedicated astrophysicists who have been investigating the mysteries of our universe.

In a landmark achievement, they have successfully simulated the intricate process of how primordial gas travels from the early universe to form a disk around a supermassive black hole.

This simulation challenges established theories and opens new frontiers in understanding the creation and evolution of black holes and galaxies.

Cosmic collaboration at its finest

Our journey begins at the esteemed Caltech, where powerhouse collaborations have birthed an exciting new discovery about the universe we inhabit.

“Our new simulation marks the culmination of several years of work from two large collaborations started here at Caltech,” says Phil Hopkins, the Ira S. Bowen Professor of Theoretical Astrophysics.

Two major collaborations nicknamed FIRE (Feedback in Realistic Environments) and STARFORGE have been diligently working on studying the cosmos on varying scales.

FIRE delves into large-scale universal phenomena such as galaxy formation, while STARFORGE zeros in on minutia, spotlighting the creation of stars in individual gas clouds.

“But there was this big gap between the two,” Hopkins explains. “Now, for the first time, we have bridged that gap.”

Previously, a significant gap existed between these two scopes of study, making it difficult to get a complete picture of the cosmic order.

But that’s all changed now, thanks to this pioneering simulation which bridges the scaling gap, delivering comprehensive insights into the dynamics of the universe.

Decoding the disks around black holes

Unveiling the secrets of the Cosmos requires not just brilliant minds, but powerful technology.

The new simulation boasts a resolution over 1,000 times greater than its previous counterparts in the field.

To the team’s surprise, as reported in The Open Journal of Astrophysics, the simulation revealed that magnetic fields play a much larger role than previously believed in forming and shaping the huge disks of material that swirl around and feed the supermassive black holes.

Long-held beliefs about black hole accretion disks, dating back to the 1970s, were challenged by the new findings.

“Our theories told us the disks should be flat like crepes. But we knew this wasn’t right because astronomical observations reveal that the disks are actually fluffy — more like an angel cake,” Hopkins explains.

“Our simulation helped us understand that magnetic fields are propping up the disk material, making it fluffier.”

The fresh insights suggest that magnetic fields, rather than thermal pressure, play an instrumental role in shaping and maintaining these huge disks.

Zooming into black holes

The team’s simulation allows what they term as a “super zoom-in” into a single supermassive black hole, similar to the ones that lie at the heart of many galaxies.

In the new simulation, the researchers performed what they call a “super zoom-in” on a single supermassive black hole, a monstrous object that lies at the heart of many galaxies, including our own Milky Way.

These ravenous, mysterious bodies contain anywhere from thousands to billions of times the mass of the sun and thus exert a huge effect on anything that comes near.

The simulation follows a giant stream of material torn off a cloud of star-forming gas and its path as it swirls around the supermassive black hole.

“We would have been very excited if we had just seen that accretion disk, but what was very surprising was that the simulated disk doesn’t look like what we’ve thought for decades it should look like.”

The advanced simulation reveals the formation of an accretion disk around the black hole, offering valuable information about the structure and behavior of these disks.

New era of astrophysics

To sum up, the new simulation developed by the Caltech team has been instrumental in not only bridging the gap between large and small scales of cosmic research but also in challenging previously held notions about black hole formation.

Their work has brought a revolutionary perspective, proving that the magnetic fields play a greater role than believed, in forming and maintaining the disks around supermassive black holes.

Accretion disks fueling black holes

In the 1970s, two important papers described the accretion disks fueling supermassive black holes. Scientists assumed that thermal pressure played the dominant role in preventing these disks from collapsing.

Thermal pressure refers to the change in pressure caused by the changing temperature of the gas in the disks. They also acknowledged that magnetic fields might play a minor role in helping to shore up the disks.

In contrast, the new simulation found that the pressure from the magnetic fields of such disks was actually 10,000 times greater than the pressure from the heat of the gas.

“So, the disks are almost completely controlled by the magnetic fields,” Hopkins says. “The magnetic fields serve many functions, one of which is to prop up the disks and make the material puffy.”

This fascinating research promisingly paves the way for a multitude of enquiries about other aspects of the universe.

From understanding what happens when galaxies merge to exploring the types of stars that form in dense galactic regions, the work by these astronomers is set to change the way we understand our universe forever.

“There’s just so much to do,” Hopkins says.

The full study was published in the journal The Open Journal of Astrophysics.


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