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Speaker |
Nieuwenhuizen, Theo M. |
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Talk Title |
Do non-relativistic neutrinos constitute the dark matter? |
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Abstract |
The dark matter of the Abell 1689 cluster is modeled by thermal fermions and its galaxies and X-ray gas by isothermal distributions. A fit yields a mass of $h_{70}^{1/2}(12/g)^{1/4}$1.445 eV. A dark matter fraction $h_{70}^{-3/2}0.1893$$ occurs for $g=12$ degrees of freedom, i. e., 6 active and 6 sterile neutrinos with masses $\approx 2^{3/4}G_F^{1/2}m_e^2$. Given a temperature of 0.045 K and a de Broglie length of 0.20 mm, they establish a quantum structure of several million light years across, the largest known in the Universe. The virial $\alpha$-particle temperature of $9.9\pm1.1$ keV$/k_B$ coincides with the one of X-rays. The results are compatible with neutrino genesis, nucleosynthesis and free streaming. The neutrinos condense on the cluster at $z\sim 28$, thereby reionizing the intracluster gas without heavy stars. The baryons are poor tracers of the dark matter density. |
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