Herschel Telescope Sees a Twisted Ring at Our Galaxy’s Center

Article Updated: 24 Dec , 2015
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From a Herschel Observatory press release:

Observations with Herschel have revealed unprecedented views of a ring in the centre of our Milky Way galaxy. The ribbon of gas and dust is more than 600 light years across and appears to be twisted, for reasons which have yet to be explained. The origin of the ring could provide insight into the history of the Milky Way.

Professor Bruce Swinyard of the Rutherford Appleton Laboratory said “Herschel’s detectors are ideally suited to see through the dust lying between us and the center of our galaxy, and to find the relatively cold material, at only 15 degrees above absolute zero, which we have learned makes up the ring.” The new results are published in a recent issue of the Astrophysical Journal Letters.

Warmer gas and dust from the center of our galaxy is shown in blue in the above image, while the colder material appears red. The ring, in yellow, is made of gas and dust at a temperature of just 15 degrees above absolute zero. The bright regions are denser, and include some of the most massive and active sites of star formation in our galaxy.

An annotated view of the 'twist' in the galactic center as seen by the Herschel telescope. Credit: ESA/NASA/JPL-Caltech

“Hints of this feature were seen in previous images of the Galactic Centre made from the ground, but no-one realised what it was,” explained Dr. Mark Thompson of the University of Hertfordshire. “It was not until the launch of Herschel, with its unparalleled wavelength coverage, that we could measure the temperature of the dust clouds and determine its true nature.”

The central region of our galaxy is dominated by a bar-like structure, which stirs up the material in the outer galaxy as it rotates over millions of years and is thought to be responsible for its spiral structure. The ring seen by Herschel lies right in the middle of this bar, encircling the region which harbors a super-massive black hole at the center of our galaxy. Professor Glenn White of The Open University and The Rutherford Appleton Laboratory said that “although bars have been seen in other galaxies, this ring of cold material revealed by Herschel, and the way it twists around the Galactic Centre, were completely unexpected, revealing several surprises.”

Firstly, the ring of gas is twisted, so from our vantage point we see two loops which appear to meet in the middle. These are seen in yellow in the image above, tilted slightly such that they run from top-left to bottom-right. Secondly, it seems to be slightly offset from the very center of our Galaxy, where a super-massive black hole lurks. “This is what is so exciting about launching a new space telescope like Herschel,” said Sergio Molinari of the Institute of Space Physics in Rome, Italy, lead author of the new paper. “We have a new and exciting mystery on our hands, right at the center of our own galaxy.”

The reason for the ring’s twist and offset are unknown, but understanding their origin may help explain the origin of the ring itself. Computer simulations indicate that bars and rings such as those we see in the center of our galaxy can be formed by gravitational interactions. It is possible that the structures in the heart of the Milky Way were caused by interactions with our largest neighbor, the Andromeda Galaxy.

“Like all good science experiments, Herschel is creating as many questions as it answers”, said Professor Matt Griffin, of the University of Cardiff, and Principle Investigator on one of Herschel’s detectors used in this study. “Unravelling the mystery of this ring could help us to explore the processes which have taken place deep in the heart of our Galaxy over billions of years.”

See the “twist” in Chromoscope or Google Sky.

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21 Responses

  1. John Durden says:

    How cool would it be if it turned out to be warped in to a mobius strip?

  2. Torbjörn Larsson says:

    I really, really hope the geometry is connected to the (difficulties of) galactic core DM models. It would be the correct size for that region of the models, no?* Maybe useful data on that as well.

    Btw, it is spooky how hard it is to kick the twisted ring pattern for me as I accidentally saw the annotated version first! There are other loops, “annotated” or not, in there but they steadily refuse to dominate the main loop.
    ———–
    * Have not checked yet. I hope if anyone knows it will be commented on.

  3. Justin Hartberger says:

    There seems to be a spherical bulge offset to the lower left of the center of the ring with some circular rings tilted off the galactic plane centered between the sphere and the annotated ring structure.

    Since the galactic center is not in the center of this ring, would there be an annoted version of this that possible has a marker for where Sag A* is in relation to this?

  4. Torbjörn Larsson says:

    There is also this:

    “A range of theoretical arguments and observational evidence make a compelling picture for a satellite infall event within our GC which triggered a brief epoch of strong starforming and AGN activity millions of years ago. When coupling the newest data – on the Fermi bubble and the dearth of old stars – to the well-established features of the GC such as the cuspy young star population, a timeline of the recent dynamical events in the galactic center emerges.”

    They claim among other things that a disturbed accretion disk (!) would not suffice to explain the current spin axis of the SMBH.

  5. Anonymous says:

    Definitely interesting. Thanks for the ‘annotated’ diagram. I couldn’t envision what was meant by the twist until then.

    • Anonymous says:

      “I couldn’t envision what was meant by the twist until then.”

      I had a bit of trouble seeing the structure clearly too. The discovery paper has a nice image of the warped dusty ring(Fig 3): http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.5486v1.pdf

      The paper also includes an informative schematic, clearly showing the off-center nature of the ring(Fig 5).

      • Anonymous says:

        cool. thanks.

      • Justin Hartberger says:

        Thanks for that Jon. That ring is massively off center from Sag A* from what they showed in the diagrams by (rough guess) about 50pc.

        In the image shown in the article, I believe it would be along the top of the lower right section of the ribbon just slightly below the vertical center of the image.

        Very interesting.

  6. Anonymous says:

    As a rule when an orbit is not fixed to a plane it means there is another gravitational perturbation. The bean shaped orbits around the Lagrange points and other lissajous type of orbits occur if the frame of the orbit is not inertial, or equivalently there is some other gravitating body, or bodies, which are perturbing the orbit.

    LC

  7. Anonymous says:

    As a rule when an orbit is not fixed to a plane it means there is another gravitational perturbation. The bean shaped orbits around the Lagrange points and other lissajous type of orbits occur if the frame of the orbit is not inertial, or equivalently there is some other gravitating body, or bodies, which are perturbing the orbit.

    LC

  8. Anonymous says:

    As a rule when an orbit is not fixed to a plane it means there is another gravitational perturbation. The bean shaped orbits around the Lagrange points and other lissajous type of orbits occur if the frame of the orbit is not inertial, or equivalently there is some other gravitating body, or bodies, which are perturbing the orbit.

    LC

  9. Anonymous says:

    As a rule when an orbit is not fixed to a plane it means there is another gravitational perturbation. The bean shaped orbits around the Lagrange points and other lissajous type of orbits occur if the frame of the orbit is not inertial, or equivalently there is some other gravitating body, or bodies, which are perturbing the orbit.

    LC

    • Anonymous says:

      Might not infalling dwarf galaxies possibly account for perturbations to this ring over time?

      A paper by Lang et al(arXiv: http://arxiv.org/PS_cache/arxiv/pdf/1107/1107.2923v1.pdf ) looked at a hypothetical merger between the Milky Way and a primordial satellite galaxy (containing a IMBH) as a possible explanation for the recently discovered gamma-ray bubbles near the nucleus and other features seen in the inner MW. In this scenario, the merger of the IMBH with the SMBH Sag A* powered the observed gamma-ray bubble itself. Other consequences of this merger would include substantial gas inflow to the inner 50 pc of the galaxy and the possible creation of the massive, young Arches ,Quintuplet and Central clusters. Infalls of dwarf galaxies would seem like one possible mechanism to produce warp seen by Herschel.

      • Anonymous says:

        Good call on this. The in-fall of mass along a direction with a large momentum component perpendicular to the galactic plane would likely cause something of this sort.

        I have a hard time wrapping my mind around a lot in this paper. There is a lot of phenomenology here I am not that familiar with. The paper addresses AGN and the “bubble” recently found along the galactic poles. This seems to rely upon the idea an intermediate mass black hole coalesced with the SMBH in the galactic core. This seems problematic. The problem is that a black hole falling onto the galactic plane is most likely to miss the galactic SMBH by light years. It would largely I think pass through the galactic plane and continue onwards, a bit like a bullet that passes through a thin wood panel. It would then maybe enter into an orbit that would take it through the galactic plane many times into the future.

        However, this could be a source for the twisted gas stream. A two body orbit conserves angular momentum, which in preserving it direction as well it means the orbit is on a constant plane. A third body that interacts with this orbit may perturb this. This would push the orbit off the constant plane if the angular momenta of the two bodies J_1 and J_2 is such that J_1*J_2 < |J_1||J_2|, * = inner product.

        LC

  10. Eric Benz says:

    is this not old news?

    very cool though – dont get me wrong.

  11. Jason Robley says:

    hey EGGHEADS………ITS THE SIGN OF THE LORD !

    MY GOD……………..WHAT WILL IT TAKE FOR U MORONS TO GET IT ! ?

    • Justin Hartberger says:

      I fail to see why this would have anything at all to do with proving or disproving an almighty being. Also, calling people morons in all caps and using “u” instead of “you” is a real winning argument.

      To quote the wise man, George Carlin – “Thou shalt keep thy religion to thyself”

  12. Anonymous says:

    It looks like the mathematical symbol for infinity.
    I realise there is no “significance” to this – I just find it satisfying…

Comments are closed.