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Most detailed hitherto simulations of a black hole solve a long-standing mystery

Most detailed hitherto simulations of a black hole solve a long-standing mystery

This image shows how the inner part of the acreage disc (red) matches the equatorial plane of the black hole. The external drive is tilted. The inner disk (where the black curve falls) is horizontal, signaling the long-standing compliance of Bardin and Petterson. Credit: Sasha Chekhovsky / Northwestern University; Matthew Lyska / University of Amsterdam

An international team has built the most fashionable, greatest resolution of the black hole simulation to date. The simulation proves theoretical predictions about the nature of the accelerated discs – an issue that orbits and ultimately falls into a black hole – which have never been seen before.

The survey will be published on June 5 at Monthly notifications by the Royal Astronomical Society.

Among the findings, a team of computational astrophysicists from Northwestern University, the University of Amsterdam and the University of Oxford found that the inner part of the acceleration disc coincides with the black hole equator.

This discovery is solved by the long-standing mystery, originally presented by Nobel Prize-winning physicist John Bardin and astrophysicist Jakob Petersensson in 1975. At that time, Barden and Petterson argued that the black hole's opening would cause the inner region of the inclined accelerating disc to align with the equatorial plane of the black hole.

After a decades-long global race to find the so-called. Bardeen-Petterson effect, the team's simulation revealed that while the outer part of the accretion disk remains tilted, the inner region of the disc coincides with the black hole. The smooth base distorts the interior and exterior regions. The team resolved the mystery by narrowing the acceleration disc to an unprecedented level and including the magnetized turbulence that cause the disc to fasten. Previous simulations made significant simplification by just approximating the effects of turbulence.

"This pioneering discovery of Bardin and Petterson's alignment led to the closure of a problem that haunts the astrophysics community for more than four decades," said Alexander Chekhovsky of the Northwest region, who led the research. "These details around the black hole may be small, but they significantly affect what happens in the galaxy as a whole. They control how fast the black holes spin and, as a result, have black holes on their galaxies."

The simulation shows the inner part of the accelerator disc that coincides with the equatorial plane of the black hole, signaling the long-standing compliance of Bardin and Petterson. Credit: Sasha Chekhovsky / Northwestern University; Matthew Lyska / University of Amsterdam

Chekhovsky is an assistant professor of physics and astronomy at Weinberg College of Arts and Sciences of Northwestern Germany and member of CIERA (Center for Interdisciplinary Research and Research in Astrophysics), Northwestern Research Center focused on the advancement of astrophysics studies with an emphasis on interdisciplinary relationships . Matthew Lisca, a researcher at the Anton Panneneck Institute of Astronomy at the University of Amsterdam, is the first author of the paper.

"These simulations not only solve the 40-year-old problem, but have shown that, contrary to typical thinking, it is possible to simulate the lightest drives to accelerate in full general relativity," said Lyska. "This paves the way for the next generation of simulations, which I hope will solve even more important problems around transparent accelerometer drives."

Failed alignment

Almost everything the researchers know about black holes are studied by studying accelerometers. Without an intensely bright ring of gas, dust, and other starbursts hanging around black holes, astronomers will not be able to spot a black hole to study it. Accretion flashes also control the growth rate and rotation of the black hole, so understanding the nature of accelerated discs is crucial to understanding how black holes develop and function.

"Harmonization affects how the ACE drives turn their black holes," said Chekhovski. "So it affects how the black hole spin evolves over time and starts outflows that affect the evolution of their host galaxies."

From Bardin and Petterson to this day, the simulations are too simplistic to find the built alignment. Two major issues acted as a barrier to computational astrophysicists. For one, the accelerator drives come so close to the black hole that they move through an arched space-time, which rushes into a black hole at a tremendous speed. Even more complicating things, the rotation of the black hole forces the space-time to spin around it. Appropriate accounting for both key effects requires general relativity, the theory of Albert Einstein that predicts how objects affect the geometry of space-time around them.

Most detailed hitherto simulations of a black hole solve a long-standing mystery

Credit: Sasha Chekhovsky / Northwestern University; Matthew Lyska / University of Amsterdam

Secondly, astrophysicists had no computing power to answer for magnetic turbulence, or interfering with the accesion disk. This mixing is what causes the disk particles to hold together in a circular shape and which causes gas to eventually fall into the black hole.

"Imagine that you have this thin drive. Then, in addition, you have to solve the turbulent movements inside the disk," said Chekhovsky. "It becomes a really difficult problem".

Without the ability to solve these features, computer scientists could not simulate real black holes.

Streaming the code

To develop a code that can perform simulations of the headline acceleration disks around the black holes, Lyska and Chekhovsky used graphic processor units (graphic units) instead of central processing units (processors). Extremely efficient in manipulating computer graphics and imaging, GPUs accelerate the creation of images on the screen. They are much more efficient than processors for calculating algorithms that process large parts of data.

Chekhovsky compares the 1.000 horsepower processors with 1,000 horses and processors with Ferrari.

Most detailed hitherto simulations of a black hole solve a long-standing mystery

Credit: Sasha Chekhovsky / Northwestern University; Matthew Lyska / University of Amsterdam

"Let's say you need to move to a new apartment," he explained. "You will have to make many trips with this powerful Ferrari because they will not fit into many boxes, but if you can put a box on each horse, you can move everything in a single moment. It's the GPU of elements, each of which is slower than those in the CPU, but there are so many of them. "

The sheet also added a method called an adaptive refinement of the aperture, which uses a dynamic network or network that changes and adapts to the flow of movement throughout the simulation. It saves energy and computing power, focusing only on specific blocks in the network where the movement takes place.

The graphics processors greatly accelerated the simulation, and the adaptive network increased the resolution. These improvements allowed the team to simulate the thinnest accretion drive to date, with a ratio of height to radius of 0.03. When the disk was simulated this slim, the researchers could see alignment next to the black hole.

"The tiniest simulated drives used to have a ratio of 0.05, and it turns out that all interesting things happen at 0.03," said Chekhovsky.

In a surprising finding, even with these incredibly slim acceleration discs, the black hole still emitted powerful particle and radiation jets.

"No one expected aircraft to be produced from these discs with such small obesity," said Chekhovsky. "People were expecting that the magnetic fields produced by these jet planes would only break down these really thin drives, but there they are, and that actually helps us solve the mysteries of observation."

The computer model shows strong magnetic fields can change the matching of black hole and plasma acoustration discs

More information:
M Liska et al, harmonization of Bardeen-Petterson, aircraft and magnetic shortening in GRMHD simulations of tilted thin accretion disks, Monthly notifications by the Royal Astronomical Society (2019). DOI: 10.1093 / mnras / stz834

Provided by
Northwestern University

Most detailed black hole simulations solve the long-standing mystery (2019, June 6)
received June 6, 2019

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