Dark matter in TGD sense corresponds to heff/h=n phases of ordinary matter associated with magnetic flux tubes carrying monopole flux. These flux tubes are n-sheeted covering spaces, and n corresponds to the dimension of the extension of rationals in which Galois group acts. The evidence for this interpretation of dark matter is accumulating. Here I discuss 4 latest galactic anomalies supporting the proposed view.
See the chapter TGD and astrophysics or the article Four new strange effects associated with galaxies .
- Standard view about galactic dark matter strongly suggests that the stars moving around so called low surface brightness stars should not have flat velocity spectrum. The surprise has been that they have. It is demonstrated that this provides additional piece of support for the TGD view about dark matter and energy assigning them with cosmic strings having galaxies as knots along them.
- The called 21-cm anomaly meaning that there is unexpected absorption of this line could be due to the transfer of energy from gas to dark matter leading to a cooling of the gas. This requires em interaction of the ordinary matter with dark matter but the allowed value of electric charge must be must much smaller than elementary particle charges. In TGD Universe the interaction would be mediated by an ordinary photon transforming to dark photon implying that em charge of dark matter particle is effectively reduced.
- The unexpected migration of stars from Milky Way halo would in pearl-in-necklace model for galaxies be due to a cosmic traffic accident: a head-on collision of galaxy arriving along cosmic string having both Milky Way and arriving galaxy along it. The gravitational attraction of the arriving galaxy would strip part of stars from the galactic plane and distributions of
stripped stars located symmetrically at the two sides of the galactic plane would be formed.
- A further observation is that the rotation period of galaxy identified as the period of rotation at the edge of galaxy seems to be universal. In TGD Universe the period could be assigned to dark matter. The model allows to build a more detailed picture about the interaction of ordinary matter and dark matter identified as a knot in a long string containing galaxies as knots. This knot would have loop like protuberances extending up to the edge of the galaxy and even beyond it. In the region or radius r of few kpc the dark matter knot behaves like a rigid body and rotates with velocity vmax slightly higher velocity vrot of distant stars. The angular rotation velocity of the flux loops extending to larger distances slows down with distance from its value ωmax at ρ=r to ωrot=vrot/R at ρ=R - roughly by a factor r/R. If stars are associated with sub-knots of the galactic knot and have decayed partially (mostly) to ordinary matter, the rotational velocities of stars and dark matter are same, and one can understand the peculiar features of the velocity spectrum.