Unravelling the mysteries of extragalactic jets

December 11, 2017, University of Leeds
Unravelling the mysteries of extragalactic jets

University of Leeds researchers have mathematically examined plasma jets from supermassive black holes to determine why certain types of jets disintegrate into huge plumes.

Their study, published in Nature Astronomy, has found that these jets can be susceptible to an never before considered as important to the jet's flow and is similar to an instability that often develops in water flowing inside a curved pipe or a rotating cylindrical vessel.

Dr Kostas Gourgouliatos conducted this research while based in the School of Mathematics at Leeds. He is now based at Durham University. He said: "These jets have a narrow oval shape which gives them a curved boundary. It is this shape that creates a weak point in the jet.

"Instability starts at the curved boundary, travels upstream on the jet and then converges at one point—what we refer to as the 'reconfinement point'. Below this point the jet stays tidy and tight but everything above will be destroyed and creates a large cosmic plume.

"When the jet disintegrates into a plume it releases heat, making them easier to spot on telescopes. The jets and their plumes are so bright that sometimes they outshine their host galaxies and are always more easily spotted than black holes, which are inferred indirectly, in space observations."

Jet breakdown. Credit: University of Leeds

The study explains why the extragalactic , which at first appear remarkably stable, may become suddenly disrupted and produce -like structures.

Study co-author Professor Serguei Komissarov, also from the School of Mathematics, said: "We did expect instability associated with velocity shear to develop at the jet reconfinement but not as fast.

"Moreover, the observed instability exhibited some rather unexpected features. In turned out that it was related to the centrifugal force acting on the fluid elements travelling along curved streamlines. This centrifugal instability is well studied but nobody expected it to be important for the jet dynamics."

Explore further: New 3-D simulations show how galactic centers cool their jets

More information: Reconfinement and Loss of Stability in Jets from Active Galactic Nuclei, Nature Astronomy, 11 December 2017. DOI: 10.1038/s41550-017-0338

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13 comments

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cantdrive85
2.2 / 5 (10) Dec 11, 2017
Once again describing plasma jets with fluid dynamics. Yet it is published by the plasma ignoramuses as having some value which it does not even come close.
Captain Stumpy
3.5 / 5 (8) Dec 11, 2017
@idiot pseudoscience eu cult acolyte illiterate
Yet it is published by the plasma ignoramuses as having some value which it does not even come close.
Once again the pseudoscience eu cult if idiots decided that a previous reference they used to support their delusional claim while being ignorant of the physics actually being described by the person who is a *plasma physicist* is now magically an ignoramus because the study above says something that they don't want to hear
RNP
3.7 / 5 (9) Dec 11, 2017
@cantdrive85
Once again describing plasma jets with fluid dynamics.... the plasma ignoramuses....

You are again showing YOUR ignorance The dictionary definition of the term fluid mechanics is "a branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas)". Did you not realise that a plasma is a fluid? Did you not realise that fluid dynamics includes the effects of ionisation?

Plasma jets MUST therefore be described using fluid dynamics. What is the alternative? Certainly not the pseudoscience that you pedal!
Chris_Reeve
Dec 11, 2017
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Chris_Reeve
Dec 11, 2017
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Chris_Reeve
Dec 11, 2017
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Chris_Reeve
Dec 11, 2017
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Solon
1.7 / 5 (6) Dec 11, 2017
Both standard model and EU have it backwards as those jets are not jets but are visible due to the radiation of an accelerated charge. The pinch in a flux tube gives rise to the sausage instability similar to those observed in solar coronal flux tubes. Charge is accelerating towards the pinch, to feed the gamma ray flare in the coronal flux tube, but our Sun and all the observed energetic phenomena such as black holes are continuous gamma ray flares of magnitudes sufficient to create matter. Solar coronal flux tubes have limited magnetic energy stored in them, while galactic scale flux tubes can feed stars for ever most likely.
Chris_Reeve
Dec 11, 2017
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Chris_Reeve
Dec 12, 2017
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tonyon
not rated yet Dec 15, 2017
Herbig Haro objects come from new stars, a electromagnetic cannon launching plasma.
tonyon
not rated yet Dec 15, 2017
ELECTROMAGNETIC WAVES turbulence, (photons) colliding against charged particles, photoelectrical effect, of the plasma-jets HH which emerge from the black holes central galactic and new young stars in formation, protostars, forming in the jet "knots" more shining each a certain distance... GRAVITATIONAL WAVES, (gravitophotons) unknown yet, come from the deep Universe since the beginning of the times. Is not a relativistic affaire "curvature" of that called "space-time".
Da Schneib
1 / 5 (2) Dec 16, 2017
How dumb does someone have to be not to realize that gas transporting ions and electrons is a current? Answer: one has to be a Thunderdolt.

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