New Image of Jet-Driven Galactic Shock Wave is a Shocker

The Chandra X-ray observatory has taken a closer look at the galaxy Centaurus A, and new images have revealed in detail the effects of a shock wave blasting through the galaxy. Powerful jets of plasma emanating from a supermassive black hole at the galactic core are creating the shock wave, and the new observation, have enabled astronomers to revise dramatically their picture of how jets affect the galaxies in which they live.

A team led by Dr. Judith Croston from the University of Hertfordshire and Dr. Ralph Kraft, of the Harvard-Smithsonian Center for Astrophysics used very deep X-ray observations from Chandra to get a new view of the jets in Centaurus A. The jets inflate large bubbles filled with energetic particles, driving a shock wave through the stars and gas of the surrounding galaxy. By analyzing in detail the X-ray emission produced where the supersonically expanding bubble collides with the surrounding galaxy, the team were able to show for the first time that particles are being accelerated to very high energies at the shock front, causing them to produce intense X-ray and gamma-ray radiation. Very high-energy gamma-ray radiation was recently detected from Centaurus A for the first time by another team of researchers using the High Energy Stereoscopic System (HESS) telescope in Namibia.

“Although we expect that galaxies with these shock waves are common in the Universe, Centaurus A is the only one close enough to study in such detail,” said Croston. “By understanding the impact that the jet has on the galaxy, its gas and stars, we can hope to understand how important the shock waves are for the life cycles of other, more distant galaxies.”

Centaurus A (NGC 5128) is one of our closest galactic neighbors, and is located in the southern constellation of Centaurus. The supermassive black hole is the source of strong radio and X-ray emissions. Visible in the image below, (click here for a zoomable image from Chandra) a combined image from Chandra and the Atacama Pathfinder Experiment (APEX) telescope in Chile, is a dust ring encircling the giant galaxy, and the fast-moving radio jets ejected from the galaxy center.

Centaurus A. Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)
Centaurus A. Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

The powerful jets are found in only a small fraction of galaxies but are most common in the largest galaxies, which are thought to have the biggest black holes. The jets are believed to be produced near to a central supermassive black hole, and travel close to the speed of light for distances of up to hundreds of thousands of light years. Recent progress in understanding how galaxies evolve suggests that these jet-driven bubbles, called radio lobes, may play an important part in the life cycle of the largest galaxies in the Universe.

Energetic particles from radio galaxies may also reach us directly as cosmic rays hitting the Earth’s atmosphere. Centaurus A is thought to produce many of the highest energy cosmic rays that arrive at the Earth. The team believes that their results are important for understanding how such high-energy particles are produced in galaxies as well as for understanding how massive galaxies evolve.

The results of this research will be published in a forthcoming issue of the Monthly Notices of the Royal Astronomical Society and were presented at the European Week of Astronomy and Space Science in the UK.

Source: RAS

20 Replies to “New Image of Jet-Driven Galactic Shock Wave is a Shocker”

  1. The link to the Zoom feature at the Chandra X-Ray Observatory is excellent. Check it out.

    “We don’t understand the environment at the galactic center very well yet,” said Elizabeth Humphreys of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

    There are several theories of how thermal friction generates magnetic fields.

    But no quantified mathematical theories.

    “Researchers assume the material is accelerated by some mechanism related to the black hole. But there are multiple theories.”

    I’d also note there is no demonstrated way for thermal friction to generate synchrotron radiation where the electrons spiral around a magnetic field at near relativitstic speed.

    But for every magnetic field there are electric currents that generate it.

    Electric fields and magnetic fields (and their concomitant electric currents) are known to cause charged particle acceleration.

    No one knows if “shock waves” cause charged particle acceleration or not.

    The post and the report rely on fluid dynamic interpretations of these observations.

    Electromagnetic interpretations would be much more informative.

    So-called “black holes”? No. A galactic plasmoid, instead.

  2. Mathematics is a description of what has been observed & measured. It quantifies physical relationships that have been already observed & measured.

    So-called “black holes” have never been directly ojbserved.

    Since nothing even approaching the ultra-high densities required of “neutron” stars (100 million tons per cubic centimeter) has ever been observed, let alone the “infinite” density required for a “black hole”, whatever that is, since “infinity” can’t be quantfied, mathematics has no insight on if ultra-high density exists in nature.

    Let me repeat:

    Mathematics has no insight or ability to state that ultra-high density is possible in nature.

    Mathematics is exclusively a postscript langauge of description of known physical relationships.

    Ultra-high density is unknown to Man.

    To subscribe to the “black hole” hypothesis is to reject Empirical Science.

    It’s that simple.

    Want it simplified further — it’s anti-Science.

    @ solrey:

    I was thinking the picture reminded me of a double layer, and the description of accelerating charged particles was exactly like how a double layer works.

    solrey, that is what you call a fine piece of analysis & re-interpretation.

    Excellent science.

    You hit it out of the park!

    Thanks for the call.


    Get to know it.

  3. Look, there’s a face in the blue part of the image. Two nostrils, tuft of hair on head above it.

    Its a sign!!!!

  4. Galaxies are surrounded by a double layer (a sheet of + charge and an adjacent sheet of – charge) “cocoon”, that seperates the plasma environment of the galaxy, from the plasma of intergalactic space. It’s known that double layers can accelerate charged particles to x-ray and gamma-ray, synchrotron energies. The “radio lobes” are where the axially, magnetic field aligned, particle beams from the central plasmoid energize that region of the double layer. The mushroom/bell shape of the double layer arises from the voltage pressure of the plasma, with those high energy particles drifting across the charge sheeth back into the outer radius of the central plane of the galaxy, flowing into the central plasmoid, where the charge density along that relatively thin sheet increases dramatically, powering the stars.

  5. I’m sure that I speak for more people than myself when I ask that you people submit your plasma theories to peer review, and let me read about it in the news when you revolutionize physics, than to keep filling up this website with posts about it. The more time you’re wasting chatting on here, the less time you’re working on your opus.

  6. On a similar note, researchers reported on interesting Xray blobs in the Northern jet in a paper “Jet heated Xray filament in the Centaurus A northern middle radio lobe” in March of this year ( Unlike the Southern lobe and its balloon shape, the Northern lobe appears knotty and bent. The paper has numerous images from XMM-Newton and Chandra. Centaurus A: the gift that keeps on giving!

  7. Notice Astrofiend and Crowell didn’t grasp the nettle of the specific points that either solrey or myself raised.

    All readers get out of their comments is general dismissive statements and misleading statements.

    Why do they resort to building strawman and then proceed to knocking them down?

    Because they don’t have strong arguments for the actual positions, evidence, and arguments presented.

    As solrey pointed out, the mathematics of electromagnetism is quite difficult and cutting edge.

    I subscribe to Galileo’s quote: “Mathematics is the language of Nature.”

    But theoretical abstraction from general principles doesn’t cut it.

    It certainly can’t prove matter can reach ultra-high densities.

    That would depend on actual observation & measurement.

    As I stated above, Science doesn’t have anything close to actual observation & measurement regarding ultra-high densities.

    100 million tons in the tip of my pinkey finger…Dream On.

    Put your thumbnail mid-way down your pinkey finger then try thinking that the exposed tip of your pinkey has 100 million tons in it…


  8. Of course something like this could never happen to the Earth because Earth isn’t in a galaxy?

    Plus, everyone knows historical catastrophes are impossible and the dinosaurs and mastodons were wiped out by the tooth fairy.

  9. Andrew Says:
    April 23rd, 2009 at 1:37 pm

    But critical examination is the arch enemy of elegant speculation! Plus you need maths to arrive at your conclusions. None ever seems to be forthcoming…

    Anaconda Says:
    April 23rd, 2009 at 12:41 pm

    “Electromagnetic interpretations would be much more informative.”

    How so? Enlighten me – what informative things can an ‘electromagnetic interpretation’ (whatever the hell that means, considering the black-hole accretion model drives jet acceleration using electromagnetic phenomena anyway) give us beyond that information already contained in the article? What further predictions can you make using your model? And where is the maths backing this statement and making your predictions?

    “So-called “black holes”? No. A galactic plasmoid, instead.”

    Hmm – where is the evidence that this is a ‘galactic plasmoid’? Where is the evidence that ‘galactic plasmoids’ even exist? How does the ‘galactic plasmoid’ explain the jet emission at the same time as the measured stellar motions in the core of such galaxies? This ‘galactic plasmoid’ must generate the energy driving the emission somehow – where do you propose this energy comes from? How does a ‘galactic plasmoid’ explain the measured variability in intrinsic luminosity of such regions, and the time-scale of variation? What is the source of the potential driving the motion of these stars (the existence of which is implied by the virial theorem) if not the gravity of a central black hole of millions of solar masses? Does a ‘galactic plasmoid’ account for the properties of the emitted spectrum from such regions, as well as the measured polarisation of the light we detect?

    “Centaurus A: the gift that keeps on giving!”

    Gotta love CenA!

  10. Anaconda Says:
    April 23rd, 2009 at 4:43 pm

    Well, that was all very deep Anaconda. Utterly wrong, but deep none-the-less. You should become a philosopher. They don’t need maths and aren’t constrained by mere observational evidence – they only need to back their ideas with more ideas. It’d be perfect for you!

  11. The reason these PU nuts object to mathematics in physics is because they don’t understand any of it.

    These galactic jets are not radio lobes. Radio lobes are due to EM radiation distrubuted as Bessel functions, which are solutions to Maxwell equation. These jets are magnetohydrodynamic in nature.

    Lawrence B. Crowell

  12. Thanks Anaconda.

    Hannes Alfven, the Nobel winning plasma physicist, suggested that double layers be treated as a new type of celestial object over twenty years ago.
    “Double layers in space should be classified as a new type of celestial object (one example is the double radio sources).”

    We’re not just making this stuff up. Nobel prize winners have been at the forefront of plasma cosmology. Mainstream is just now starting to catch up.

    Who said there was no need for math in EU theory? The math of plasma physics is about as complicated as it gets. But at least it applies to the real world.

  13. @lbc
    Nobody said that the jets were radio lobes. We’re saying that the double layer that the jets interact with are the radio lobes.
    Plus, I’m not aware of any EU proponents that object to math in physics. Actually, most EU proponents are quite savvy with advanced math. It’s the reliance on abstract, theoretical math, in favor of experiment and observation, that we object to.
    I understand math quite well, btw.

  14. Can the webmaster please remove these idiots’ comments?
    If you have nothing interesting to say, please refrain from saying it and ruining things for the rest of us.

  15. @darkgnat
    That’s an animation from ESO. Here’s how they describe it:

    “The actual images, that have been collected over the past 16 years, are assembled in this video. The real motion of the stars has been accelerated by a factor 32 millions. The individual images have been shifted and stretched to the same scale and orientation…”

    It’s just an animation made from a collection of images over the course of 16 years. They left the center black for visual clarity,
    Your analysis is totally un-informed and erroneous.
    Here’s what’s at the core of our galaxy:

    So you want to censor those ‘jerks’ you don’t agree with? Nice. Real nice. Let’s just go back to the Inquisition while we’re at it.

  16. Dark Gnat Says:
    April 24th, 2009 at 8:54 am
    So exaclty how does EU explain this?

    ^ Observations of stars orbiting…”nothing”…in the center of the galaxy. That’s basically proof that black holes exist.

    This goes back to Wheeler’s analogue of watching men and women dancing. The men in black tuxs are not seen while the women in white gowns are seen swirling around. This data is clearly present in the galaxy center, and the “man” in this case is about 100 million solar masses, with lots of girls swirling around. There are no known material structures which can exist in a stable manner with that much mass. Early investigation of hyperstars demonstrated that stars larger than ~ 100 solar masses can’t exist. This looks pretty much like a thundering large black hole!

    Of course we can’t observe the event horizon, by definition. Yet the gravitational physics outside the event horizon can be observed and shown to be unique to a black hole. This is good observational support for the existence of a black hole.

    Contrary to what what some EU/PU people think, science is not about proving things or about aboslute truth. Science only observes things which support theoretical understanding, which are themselves only tentatively true within some domain of experience or observation.

    Lawrence B. Crowell

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