Wobbling galaxies: New evidence for dark matter

In summary, astronomers have discovered that the brightest galaxies in galaxy clusters exhibit a "wobbling" motion that is inconsistent with predictions of the current standard model of dark matter. This could potentially provide insights into the nature of dark matter and suggest the presence of new physics. However, the need for self-interacting dark matter to explain this phenomenon is in conflict with other astrophysical data, such as the Cosmic Microwave Background and indirect detection probes. Therefore, future research in this area must address these constraints in order to develop a more complete understanding of dark matter.
  • #1
wolram
Gold Member
Dearly Missed
4,446
558
https://www.sciencedaily.com/releases/2017/10/171026103110.htm

Astronomers have discovered that the brightest galaxies within galaxy clusters 'wobble' relative to the cluster's center of mass. This unexpected result is inconsistent with predictions made by the current standard model of dark matter. With further analysis it may provide insights into the nature of dark matter, perhaps even indicating that new physics is at work.

Is this a matter of incorrect observation or is it real?
 
Astronomy news on Phys.org
  • #2
wolram said:
https://www.sciencedaily.com/releases/2017/10/171026103110.htm

Astronomers have discovered that the brightest galaxies within galaxy clusters 'wobble' relative to the cluster's center of mass. This unexpected result is inconsistent with predictions made by the current standard model of dark matter. With further analysis it may provide insights into the nature of dark matter, perhaps even indicating that new physics is at work.

Is this a matter of incorrect observation or is it real?

The press release at Science Daily notes near the end that:

If this "wobbling" is not an unknown astrophysical phenomenon and in fact the result of the behaviour of dark matter, then it is inconsistent with the standard model of dark matter and can only be explained if dark matter particles can interact with each other -- a strong contradiction to the current understanding of dark matter.

The wobbling observation is very likely to be real as it is a close analogy of the long known "cusp-core" problem with Cold Dark Matter. See, e.g., https://arxiv.org/pdf/1305.7452v2.pdf

But, the need for self-interacting dark matter (SIDM) to solve the problem is huge, because all astrophysically relevant parameters for SIDM have been ruled out by other data. See:

Torsten Bringmann, et al., "Strong constraints on self-interacting dark matter with light mediators" (December 2, 2016). Abstract:

Coupling dark matter to light new particles is an attractive way to combine thermal production with strong velocity-dependent self-interactions. Here we point out that in such models the dark matter annihilation rate is generically enhanced by the Sommerfeld effect, and we derive the resulting constraints from the Cosmic Microwave Background and other indirect detection probes. For the frequently studied case of s-wave annihilation these constraints exclude the entire parameter space where the self-interactions are large enough to address the small-scale problems of structure formation.

The conclusion of the paper notes that:

Models of DM with velocity-dependent self-interactions have recently received a great deal of attention for their potential to produce a number of interesting effects on astrophysical scales. We have shown in this Letter that these models face very strong constraints from the CMB and DM indirect detection. In the most natural realization of this scenario with a light vector mediator with kinetic mixing, these constraints rule out the entire parameter space where the self-scattering cross section can be relevant for astrophysical systems. These bounds remain highly relevant for a number of generalizations of the scenario, such as a different dark sector temperature and different mediator branching ratios. Clearly, future efforts to develop particle physics models for SIDM need to address these issues in order to arrive at models that provide a picture consistent with all observations in cosmology, astrophysics and particle physics.
 
  • Like
Likes wolram

1. What is wobbling galaxies?

Wobbling galaxies refer to the observed irregular movements of galaxies within galaxy clusters. These movements cannot be explained by the gravitational pull of visible matter alone, leading scientists to believe that there must be an unseen force at work, such as dark matter.

2. How does this provide evidence for dark matter?

The wobbling of galaxies cannot be explained by the known laws of gravity, which only take into account visible matter. This suggests that there must be an additional source of mass, which we cannot see, and is therefore referred to as dark matter.

3. What is dark matter and why is it important?

Dark matter is a hypothetical form of matter that is believed to make up about 85% of the total mass of the universe. It does not interact with light, making it invisible, and its existence is inferred through its gravitational effects on visible matter. Understanding dark matter is important because it plays a crucial role in the formation and evolution of galaxies and the overall structure of the universe.

4. How was this evidence for dark matter discovered?

The evidence for dark matter was first observed in the 1930s when astronomer Fritz Zwicky noticed that the mass of the Coma galaxy cluster could not be explained by the visible matter alone. Since then, various studies, including the observation of wobbling galaxies, have provided further evidence for the existence of dark matter.

5. Could there be other explanations for wobbling galaxies?

While scientists continue to explore alternative theories, the current evidence strongly supports the existence of dark matter as the most likely explanation for the wobbling of galaxies. However, further research and observations are needed to fully understand the nature of dark matter and its role in the universe.

Similar threads

  • Astronomy and Astrophysics
Replies
7
Views
2K
  • Astronomy and Astrophysics
Replies
4
Views
2K
  • Astronomy and Astrophysics
Replies
6
Views
1K
  • Astronomy and Astrophysics
Replies
2
Views
2K
  • Astronomy and Astrophysics
2
Replies
65
Views
7K
  • Astronomy and Astrophysics
Replies
1
Views
1K
  • Astronomy and Astrophysics
Replies
3
Views
2K
  • Astronomy and Astrophysics
Replies
24
Views
4K
Replies
35
Views
2K
  • Beyond the Standard Models
8
Replies
264
Views
14K
Back
Top