RAS: Interactive Dark Matter and Missing Satellite Galaxies

[bystander]

Interactive Dark Matter Could Explain Milky Way's Missing Satellite Galaxies
Durham University | Royal Astronomical Society | 2014 Sep 08

The simulated distribution of dark matter in a Milky Way-like galaxy for standard, non-interacting dark matter (top left), warm dark matter (top right) and the new dark matter model that interacts with the photon background (bottom). Smaller structures are erased up to the point where, in the most extreme model (bottom right), the galaxy is completely sterilized. [b][i](Credit: Durham University)[/i][/b]

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Scientists believe they have found a way to explain why there are not as many galaxies orbiting the Milky Way as expected. Computer simulations of the formation of our galaxy suggest that there should be many more small galaxies around the Milky Way than are observed through telescopes.

This has thrown doubt on the generally accepted theory of cold dark matter, an invisible and mysterious substance that scientists predict should allow for more galaxy formation around the Milky Way than is seen.

Now cosmologists and particle physicists at the Institute for Computational Cosmology and the Institute for Particle Physics Phenomenology, at Durham University, working with colleagues at LAPTh College & University in France, think they have found a potential solution to the problem.

Writing in the journal Monthly Notices of the Royal Astronomical Society (MNRAS), the scientists suggest that dark matter particles, as well as feeling the force of gravity, could have interacted with photons and neutrinos in the young universe, causing the dark matter to scatter.

Scientists think clumps of dark matter -- or halos -- that emerged from the early universe, trapped the intergalactic gas needed to form stars and galaxies. Scattering the dark matter particles wipes out the structures that can trap gas, stopping more galaxies from forming around the Milky Way and reducing the number that should exist. ...

Using the Milky Way satellites to study interactions between cold dark matter and radiation - C. Boehm et al

• Monthly Notices of the RAS, Letters 445(1) L31 (2014 Nov 21) DOI: 10.1093/mnrasl/slu115
  arXiv.org > astro-ph > arXiv:1404.7012 > 28 Apr 2014 (v1), 19 Aug 2014 (v2)

[bystander]

A Warm Dark Matter Search Using XMASS
KAVLI IPMU | University of Tokyo | 2014 Oct 03

XMASS collaboration, led by Yoichiro Suzuki at the Kavli IPMU, has reported latest results on warm dark matter search. Their results rule out the possibility that super-weakly interacting massive bosonic particles (Bosonic super-WIMPs) constitute all dark matter in the universe. This result was published in September 19th issue of the Physical Review Letters as an Editors’ Suggestion.

The universe is considered to be filled with dark matter, which cannot be observed by ordinary light. Although much evidence supports the existence of dark matter, it has yet to be directly detected and its nature is not understood.

Various theoretical models have been proposed to explain the nature of dark matter. Some models extend the standard model of particle physics, such as super-symmetry, and suggest that weakly interacting massive particles (WIMPs) are dark matter candidates. These models have motivated most research on experimental dark matter. In discussions on the large-scale structure formation of the universe, these WIMPs fit the cold dark matter (CDM) paradigm.

On the other hand, some simulations based on the CDM scenario predict a much richer structure of the universe on galactic scales than those observed. Furthermore, high-energy collider experiments have yet to provide evidence of super-symmetric particles. These facts have increased the interest in lighter and further weakly interacting particles such as bosonic super-WIMPs as dark matter. Super-WIMPs with masses greater than a twentieth of an electron (more than 3 keV) do not conflict with the structure formation of the universe. ...

Search for bosonic superweakly interacting massive dark matter particles with the XMASS-I detector - K. Abe et al (XMASS Collaboration)

• Physical Review Letters 113(12) 121301 (19 Sep 2014) DOI: 10.1103/PhysRevLett.113.121301
  arXiv.org > astro-ph > arXiv:1406.0502 > 02 Jun 2014 (v1), 21 Aug 2014 (v3)