J-E-T-S, Jets, Jets, Jets!

Article written: 25 Nov , 2010
Updated: 24 Dec , 2015
by

[/caption]

It seems oddly appropriate to be writing about astrophysical jets on Thanksgiving Day, when the New York football Jets will be featured on television. In the most recent issue of Science, Carlos Carrasco-Gonzalez and collaborators write about how their observations of radio emissions from young stellar objects (YSOs) shed light one of the unsolved problems in astrophysics; what are the mechanisms that form the streams of plasma known as polar jets? Although we are still early in the game, Carrasco-Gonzalez et al have moved us closer to the goal line with their discovery.

Astronomers see polar jets in many places in the Universe. The largest polar jets are those seen in active galaxies such as quasars. They are also found in gamma-ray bursters, cataclysmic variable stars, X-ray binaries and protostars in the process of becoming main sequence stars. All these objects have several features in common: a central gravitational source, such as a black hole or white dwarf, an accretion disk, diffuse matter orbiting around the central mass, and a strong magnetic field.

Relativistic jet from an AGN. Credit: Pearson Education, Inc., Upper Saddle River, New Jersey

When matter is emitted at speeds approaching the speed of light, these jets are called relativistic jets. These are normally the jets produced by supermassive black holes in active galaxies. These jets emit energy in the form of radio waves produced by electrons as they spiral around magnetic fields, a process called synchrotron emission. Extremely distant active galactic nuclei (AGN) have been mapped out in great detail using radio interferometers like the Very Large Array in New Mexico. These emissions can be used to estimate the direction and intensity of AGNs magnetic fields, but other basic information, such as the velocity and amount of mass loss, are not well known.

On the other hand, astronomers know a great deal about the polar jets emitted by young stars through the emission lines in their spectra. The density, temperature and radial velocity of nearby stellar jets can be measured very well. The only thing missing from the recipe is the strength of the magnetic field. Ironically, this is the one thing that we can measure well in distant AGN. It seemed unlikely that stellar jets would produce synchrotron emissions since the temperatures in these jets are usually only a few thousand degrees. The exciting news from Carrasco-Gonzalez et al is that jets from young stars do emit synchrotron radiation, which allowed them to measure the strength and direction of the magnetic field in the massive Herbig-Haro object, HH 80-81, a protostar 10 times as massive and 17,000 times more luminous than our Sun.

Finally obtaining data related to the intensity and orientation of the magnetic field lines in YSO’s and their similarity to the characteristics of AGN suggests we may be that much closer to understanding the common origin of all astrophysical jets. Yet another thing to be thankful for on this day.

, , , , ,



21 Responses

  1. tjaracas says

    So once one might the use astrophysics to create polar jets in a controlled environment to power a spaceship. That way we can travel in about 20 years to porixmo centauri.

  2. GBendt says

    “The exciting news from Carrasco-Gonzalez et al is that jets from young stars do emit synchrotron radiation, which allowed them to measure the strength and direction of the magnetic field in the massive Herbig-Haro object, HH 80-81, a protostar 10 times as massive and 17,000 times more luminous than our Sun.! —

    I would rather love to know the results of the measurement of that magnetic field by Carrasco-Gonzalez et al, and by which method these results were obtained.

  3. Here’s the article: T Ray 2010 Science 330 1184-6 Cosmic Rays from Cosmic Birth.
    Link: [http://www.sciencemag.org/content/330/6008/1184.full?rss=1]
    It’s a very significant result, which (at last) unifies nano-, micro-, milli-, kilo- … & … mega-, giga-quasars!

    There may be a resonant acceleration mechanism at play to get relativistic spped. One such mechanism was suggested for SS433, a (so-called) microquasar.

  4. Lawrence B. Crowell says

    The mechanism involves a huge amount of energy, which is likely a black hole. The large gravity pit has a huge gravitational potential energy, where a small percentage of this can be converted to kinetic and thermal energy. The accretion disk of material orbiting the black hole heats up due to hydrodynamic friction. Once this is hot enough the gas ionizes. Ions and electrons have different transport properties which, establishes charge and current separations, and the MHD dynamo. The variable magnetic field acts as some type of accelerator. The chromosphere of the sun is hotter than the direct surface due to magnetohydrodynamic heating by magnetic field variations. Something similar to this is transferring energy to charged species in the accretion disk and accelerating those outwards.

    LC

  5. DrFlimmer says

    Well, it doesn’t need to be a black hole. A forming star does the trick as well. What you need is an accretion disk and magnetic field (and it is not yet clear if they are self-made or if they have to be around before the disk forms).
    However, this trick (to build jets) is quite important. It is possibly the only way to get material from the disk onto the central object (might that be a star or a black hole). Why is that?
    The problem is angular momentum, which needs to be conserved all the time similar to energy or momentum. So, in order to get things lose their angular momentum some other things nearby must gain a lot. Some particles are trapped by the magnetic fields and due to whatever reason (as one can see, many things are not understood quite well) they are accelerated along the rotational axis of the system and shoot out at hight speed. Since they are on a spiral path and are pretty fast, they take away a lot of angular momentum which causes other particles to hit the central object.

    That’s the idea (just to follow up on Lawrence B. Crowell’s comment), but there’s still a lot to do.

    It is good that finally there is evidence for synchrotron radiation of Herbig Haro objects (or jets of young stars). This underpins the idea that jets have a common cause. It is only the power of the jets that seems to be different from type to type. One could argue that this is due to the mass of the central object (and maybe its angular momentum).

  6. Lawrence B. Crowell says

    DrFlimmer, For smaller jets that is the case. I suppose I was thinking of active galactic nuclei jets.

    LC

  7. Member
    Aqua says

    What if we find a black hole and accretion disk at the center of every atom? Fractals thereof might then include stars, clusters and galaxies?

  8. Torbjorn Larsson OM says

    I *love* then it comes together!

    (Not that the other case of wholly new physics isn’t any less lovable!)

    Why do I talk in all !’s !? (Guess I’m excited!)

  9. jimhenson says

    atoms likely have self-similar fractal structures to galaxies. the s orbital is spherical, and could be an accretion disk. Clockwise or retrograde spin is just one quanta energy unit difference for an electron. the huge milky way bubbles of x-rays gamma rays, are electrons moving near relativistic speeds. robert oldershaw says the milky way is self-similar to a carbon or oxygen atomic nucleus. gamma rays can be produced by electric field disruption at the atomic nucleus, and even our G D galaxy agn could be EM forces. not inferred black holes

  10. Member
  11. Jon Hanford says

    A version of this paper first published in ‘Science’ is now available: http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.6254v1.pdf

  12. jimhenson says

    up crumb’s behind. expert authority quoted on my site explains the milky way is self-similar to an atomic C or O nucleus. 2 s N-S polar orbiting electrons spins in opposite directions, to prevent hitting the nucleus, causing atomic accretion disk, magnetic field and jets. protostar iras 18162-2048 has a 17 light year long tail jet, and our galaxy a 50,000 LY bipolar xray gamma ray lobes. EM forces observationally explain away your dark matter crap and stupid big bang model for a 90% invisible undetectable universe. all stars produce jets the same way supernovas and galaxies do says Carrasco-Gonzalez. black holes are inferred to only be in SN and BH, not stars nor atoms. this discovery takes 12 hours time per star so is not repeated, but shows what EM plasma charges do, to attract and shape the universe at the largest scales without requiring big bang DM and BH’s.

  13. Hon. Salacious B. Crumb says

    Eh?

    “atoms likely have self-similar fractal structures to galaxies. the s orbital is spherical, and could be an accretion disk. Clockwise or retrograde spin is just one quanta energy unit difference for an electron. the huge milky way bubbles of x-rays gamma rays, are electrons moving near relativistic speeds. robert oldershaw says the milky way is self-similar to a carbon or oxygen atomic nucleus. gamma rays can be produced by electric field disruption at the atomic nucleus, and even our G D galaxy agn could be EM forces. not inferred black holes.”

    You are really in la la land, jerk off!

  14. Hon. Salacious B. Crumb says

    Ah, Muppet! Now the truth! “expert authority quoted on my site…”

    So again you are promoting yourself and agenda again the UT guidelines. (It was also rightly deleted many of your nutty UT post)

    Frankly all you talk is utter random gibberish — words without any real context. PLEASE, WHERE IS THE ACTUAL EVIDENCE FOR ALL YOUR SILLY STATEMENTS!

    It opinion, and what is worst, it is YOUR opinion!

    Also have you noticed ‘atoms’ are not even mentioned in the article, so what the hell has this to do with this story?

    Methinks you don’t have a clue in what you are talking about! (I’d mark you 10/10, though, for the overactive imagination!)

  15. jimhenson says

    like i said, Carrasco-Gonzalez states jets are produced the same way in stars, suoernovas, and agn galaxies. we all know here that stars including neutron stars, do not have a black hole! Black holes are inferred, yet produce jets the same way that stars do is what this authority proved discovered. there’s no way anybody can tell me that gravity alone is forming protostars having 17 LY long tails of plasma! gravity makes round planets and stars, and is strongest at shorter distances, but EM forces increase with increasing distance, and shape the universe. black holes are not necessary. these are facts, not silly gibberish like the universe was once a dense hot singularity and blew up. your universe is very very tiny, compared to mine. since nobody comes here to read this late nobody nothing is being disrupted here at UT. some of crumb’s posts need to be deleted in the ongoing future, because he is beligerant and disrespectful, liking to insult someone into going away. he’s just a jerk

  16. Hon. Salacious B. Crumb says

    zzzzzzzzzzzzzzzzzz…..

  17. Hon. Salacious B. Crumb says

    “some of crumb’s posts need to be deleted in the ongoing future, because he is beligerant and disrespectful, liking to insult someone into going away. he’s just a jerk”

    Eh? Facts? Idiots like you wouldn’t know a fact if it slapped you in the face!

    Looks like the ol’ Muppet is getting desperate. Enough of your obvious ridiculous diatribe. I promised I’d bury you, and your already in the coffin and half the nails have already been hammered in.

    Plasma cosmology is absolute crap!!

    I know it, and everyone else knows it, except for a handful of deluded jackasses like you and your imaginary deluded friend. Wake up dimwit, your living in the dim dark ages of prehistoric history! Your are just about to become extinct, like the dodo and T Rex! Bye bye, sugar,,,,

  18. jimhenson says

    what a coward to threaten my life

  19. Hon. Salacious B. Crumb says

    Life, what life? Kill you? Are you that real naive…
    I want to bury your very stupid, illogical, mumbo jumbo ideas. I.e. Plasma cosmology absolute is crap!
    Just playing the victim card isn’t going to get you any sympathy here.
    Man up sunshine!

  20. jimhenson says

    the big bang is absolute crap and crumb lives in it. PC is not the ultimate cosmology, but is the best today until we get better telescopes to see older galaxies and entire superclusters that take up to 80 billion years to form already. nasa will study the dark flow cosmic axial dipole that aligns with the fine-structure constant that varies like all constants including gravity and c. obviously a huge black hole or EM pinch 150 BLY distance will disprove the big bang and yank out the heads up the butts of fools like where crumb’s head is currently placed. crumbo believes the crap he chooses likes the stink fill to believe in, instead of studying new science everyday.

  21. OK guys. Comments are now closed on this article since you’ve gone off topic and off the deep end on attacking each other.

Comments are closed.