New Research Shows Dark Matter Might Not Be Interactive After All

Dark Matter Might Not Be Interactive

Hubble Space Telescope image of the four giant galaxies at the heart of cluster Abell 3827. An almost 3-hour exposure shows the view at wavelengths visible to the human eye, and the near infrared, as used in the original 2015 study. The distorted image of a more distant galaxy behind the cluster is faintly visible, wrapped around the four galaxies. Credit: NASA/ESA/Richard Massey (Durham University)

Astronomers are back in the dark about what dark matter might be, after new observations showed the mysterious substance may not be interacting with forces other than gravity after all. Dr. Andrew Robertson of Durham University will today (Friday 6 April) present the new results at the European Week of Astronomy and Space Science in Liverpool.

Three years ago, a Durham-led international team of researchers thought they had made a breakthrough in ultimately identifying what dark matter is.

Observations using the Hubble Space Telescope appeared to show that a galaxy in the Abell 3827 cluster – approximately 1.3 billion light years from Earth – had become separated from the dark matter surrounding it.

Cluster Abell 3827

A view of the four central galaxies at the heart of cluster Abell 3827, at a broader range of wavelengths, including Hubble Space Telescope imaging in the ultraviolet (shown as blue), and Atacama Large Millimeter Array imaging at very long (sub-mm) wavelengths (shown as red contour lines). At these wavelengths, the foreground cluster becomes nearly transparent, enabling the background galaxy to be more clearly seen. It is now easier to identify how that background galaxy has been distorted. Credit: NASA/ESA/ESO/Richard Massey (Durham University)

Such an offset is predicted during collisions if dark matter interacts with forces other than gravity, potentially providing clues about what the substance might be.

The chance orientation at which the Abell 3827 cluster is seen from Earth makes it possible to conduct highly sensitive measurements of its dark matter.

However, the same group of astronomers now say that new data from more recent observations show that dark matter in the Abell 3827 cluster has not separated from its galaxy after all. The measurement is consistent with dark matter feeling only the force of gravity.

Abell 3827

A wide-field optical image of galaxy cluster Abell 3827. Credit: ESO

Lead author Dr. Richard Massey, in the Center for Extragalactic Astronomy, at Durham University, said: “The search for dark matter is frustrating, but that’s science. When data improves, the conclusions can change.”

“Meanwhile the hunt goes on for dark matter to reveal its nature.”

“So long as dark matter doesn’t interact with the Universe around it, we are having a hard time working out what it is.”

The Universe is composed of approximately 27 percent dark matter with the remainder largely consisting of the equally mysterious dark energy. Normal matter, such as planets and stars, contributes a relatively small five percent of the Universe.

There is believed to be about five times more dark matter than all the other particles understood by science, but nobody knows what it is.

Superpressure Balloon-borne Imaging Telescope (SuperBIT)

The Superpressure Balloon-borne Imaging Telescope (SuperBIT) has just been built by an international team of scientists and engineers from Durham University, Princeton University, the University of Toronto, and NASA’s Jet Propulsion Laboratory. The telescope achieves an uninterrupted view of the night sky by rising above 99 percent of the Earth’s atmosphere under a helium balloon the size of a football stadium. This novel route into space costs a tiny fraction of a rocket launch and is far quicker to design. Following two successful test flights, SuperBIT is scheduled to fly for three months from New Zealand in 2019. From there, it will measure the distribution of dark matter around 200 galaxy clusters, something that would have been impossible using existing technology like the Hubble Space Telescope. Photo credit: SuperBIT/Richard Massey.

However, dark matter is an essential factor in how the Universe looks today, as without the constraining effect of its extra gravity, galaxies like our Milky Way would fling themselves apart as they spin.

In this latest study, the researchers used the Atacama Large Millimeter Array (ALMA) in Chile, South America, to view the Abell 3827 cluster.

ALMA picked up on the distorted infrared light from an unrelated background galaxy, revealing the location of the otherwise invisible dark matter that remained unidentified in their previous study.

A supercomputer simulation of a collision between two galaxy clusters, similar to the real object known as the ‘Bullet Cluster’, and showing the same effects tested for in Abell 3827. All galaxy clusters contain stars (orange), hydrogen gas (shown as red) and invisible dark matter (shown as blue). Individual stars, and individual galaxies are so far apart from each other that they whizz straight past each other. The diffuse gas slows down and becomes separated from the galaxies, due to the forces between ordinary particles that act as friction. If dark matter feels only the force of gravity, it should stay in the same place as the stars, but if it feels other forces, its trajectory through this giant particle collider would be changed. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University

Research co-author Professor Liliya Williams, of the University of Minnesota, said: “We got a higher resolution view of the distant galaxy using ALMA than from even the Hubble Space Telescope.”

“The true position of the dark matter became clearer than in our previous observations.”

While the new results show dark matter staying with its galaxy, the researchers said it did not necessarily mean that dark matter does not interact. Dark matter might just interact very little, or this particular galaxy might be moving directly towards us, so we would not expect to see its dark matter displaced sideways, the team added.

Several new theories of non-standard dark matter have been invented over the past two years and many have been simulated at Durham University using high-powered supercomputers.

A simulation of the same collision if dark matter consisted of extremely strongly ‘self-interacting’ particles that feel large forces in addition to gravity. The resulting distribution of dark matter and gas disagrees with what is observed in the real Universe – indeed, the interaction is so strong in this case that the dark matter stopped close to the point of impact. Since this is not seen in the real Universe, this enables us to rule out this particular model of dark matter. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University

Robertson, who is a co-author of the work, and based at Durham University’s Institute for Computational Cosmology, added: “Different properties of dark matter do leave tell-tale signs.”

“We will keep looking for nature to have done the experiment we need, and for us to see it from the right angle.”

“One especially interesting test is that dark matter interactions make clumps of dark matter more spherical. That’s the next thing we’re going to look for.”

To measure the dark matter in hundreds of galaxy clusters and continue this investigation, Durham University has just finished helping to build the new SuperBIT telescope, which gets a clear view by rising above the Earth’s atmosphere under a giant helium balloon.

The research was funded by the Royal Society and the Science and Technology Facilities Council in the UK and NASA. The findings will appear in a new paper in the journal Monthly Notices of the Royal Astronomical Society.

A simulation of the same collision if dark matter didn’t exist. The resulting distribution of stars and gas disagrees with what is observed in the real Universe, which provides compelling evidence that dark matter is present in the real Universe. Credit: Andrew Robertson/Institute for Computational Cosmology/Durham University

Reference: “Dark matter dynamics in Abell 3827: new data consistent with standard Cold Dark Matter” by Richard Massey, David Harvey, Jori Liesenborgs, Johan Richard, Stuart Stach, Mark Swinbank, Peter Taylor, Liliya Williams, Douglas Clowe, Frédéric Courbin, Alastair Edge, Holger Israel, Mathilde Jauzac, Rémy Joseph, Eric Jullo, Thomas D Kitching, Adrienne Leonard, Julian Merten, Daisuke Nagai, James Nightingale, Andrew Robertson, Luis Javier Romualdez, Prasenjit Saha, Renske Smit, Sut-Ieng Tam and Eric Tittley, 17 April 2018, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/sty630

2 Comments on "New Research Shows Dark Matter Might Not Be Interactive After All"

  1. Sankaravelayudhan Nandakumar | November 16, 2018 at 6:08 pm | Reply

    Citation:Electrons of opposite magneticfield as cross dynamics producing halls thrust in forming super conductive electrons a specific band widths with dark matter stripes in between separating 12 magneto optic quantum sector as a relative collections in between
    Hawkings radiation must have 12 fire , earth air water ,repeated sectors surrounding a blackhole with dark matter stripes in between

    The sensitive and wide-ranging datasets enabled the scientists to probe the thermodynamic character and motions of the hot gas (including both infall and outflow streams), the cold, star forming dust clouds in the galaxy, and the relative spatial arrangement of all these ingredients. They find detailed support for the models, including both infall of hot material into the galaxy and its subsequent conversion into new stars and as well the outflow of gas driven by jets from the central supermassive black hole. They show that the warm and cold material are actually found together in this galaxy (although they are of different densities), with clouds of cold gas likely feeding the black hole and apparently coupling to the powerful jets ejected from the nucleus.
    The result is that the molecular and ionized nebula at the heart of Abell 2597 is what they term a galaxy-scale “fountain:” cold gas drains into the reservoir created by the presence of the black hole at the center, and this powers outflowing jets that, in turn, later cool and sink, raining back down. Because the outflowing material does not move quickly enough to escape the galaxy’s gravity, they conclude that this dramatic galactic fountain seems likely to be long-lived. It may also be a common occurrence in these massive clusters, helping to explain the cosmic evolution of galaxies. This illustration depicts the view from outside of a rapidly-accreting black hole. The bright light toward the center represents the super-heating of gas as it falls onto the black hole. Emanating from the center is a jet of accelerated particles moving near the speed of light. Surrounding the black hold is cool, clumpy gas and dust, which are falling inwards and will eventually join the material accreting onto the black hole.

  2. Dr. Benjamin Gal-Or | September 24, 2020 at 3:32 am | Reply

    2016-2018 Borlaff et al discoveries resort to various old Hubble Telescope Deep-Space records [Astrop. J. ”in”, etc], which, by their revealing unclear data, shed new light on ousted outer layers of galaxies and massive stars that leave behind dark expanding spaces surrounded by rings of stars – (1) Thermodynamic Glossary – Stellar Radiation Pressure, SRP, equals a constant times T, times T, times T, times T, where T is Star or galactic emitter Core Temperature – (2) SRG equals core gravity in stable systems – (3) Borlafff et al results show SRG-pushed-out rings of stars that leave behind expanding dark spaces -(4) Core Gravity then causes collapse to neutron stars, or black holes or bouncing-out supernovae [massive stars] – (5) SRG of Stellar-Galactic Winds, [SGW], that irreversibly dissipate in each observed expanding-cooling, coldest (-270C) Large Intergalactic Voids, [LIV], Compacts galaxies there into Superclusters that that SRG drives away from each other faster then only by Hubble-World Expansion, HWE, thus accelerating the slowing down HWE when SRG increases, later in the universe age – (6) Similar thermodynamics, via Borlaff et al’s results, indicate new conclusions regarding the generation of dark spaces that separate Arms in spiral galaxies [”in”].

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