Berkeley: How Black Hole Jets Break Out of Their Galaxies

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bystander
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Berkeley: How Black Hole Jets Break Out of Their Galaxies

Post by bystander » Fri Jun 17, 2016 3:37 pm

Breakout: How Black Hole Jets Break Out of Their Galaxies
University of California, Berkeley | 2016 jun 16

A simulation of the powerful jets generated by supermassive black holes at the centers of the largest galaxies explains why some burst forth as bright beacons visible across the universe, while others fall apart and never pierce the halo of the galaxy.
Click to play embedded YouTube video.

About 10 percent of all galaxies with active nuclei -- all presumed to have supermassive black holes within the central bulge -- are observed to have jets of gas spurting in opposite directions from the core. The hot ionized gas is propelled by the twisting magnetic fields of the rotating black hole, which can be as large as several billion suns.

A 40-year-old puzzle was why some jets are hefty and punch out of the galaxy into intergalactic space, while others are narrow and often fizzle out before reaching the edge of the galaxy. The answer could shed light on how galaxies and their central black holes evolve, since aborted jets are thought to roil the galaxy and slow star formation, while also slowing the infall of gas that has been feeding the voracious black hole. The model could also help astronomers understand other types of jets, such as those produced by individual stars and we see as gamma-ray bursts or pulsars. ...

If the jet is not powerful enough to penetrate the surrounding gas, the jet becomes narrow and collimated, a shape prone to kinking and breaking. When this happens, the hot ionized gas funneled through the magnetic field spews into the galaxy, inflating a hot bubble of gas that generally heats up the galaxy.

Powerful jets, however, are broader and able to punch through the surrounding gas into the intergalactic medium. The determining factors are the power of the jet and how quickly the gas density drops off with distance, typically dependent on the mass and radius of the galaxy core. ...

Three-dimensional Relativistic MHD Simulations of Active Galactic Nuclei Jets:
Magnetic Kink Instability and Fanaroff-Riley Dichotomy
- Alexander Tchekhovskoy, Omer Bromberg
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neufer
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Re: Berkeley: How Black Hole Jets Break Out of Their Galaxies

Post by neufer » Fri Jun 17, 2016 5:50 pm

Click to play embedded YouTube video.
Art Neuendorffer

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