A natural explanation of the Galactic Magnetic Fields from multistate Scalar Field Dark Matter

In this article, we investigate the possibility that the large-scale magnetic fields observed in galaxies, of the order of microgauss, arise naturally from a complex Scalar Field Dark Matter (SFDM) halo charged under a local $U(1)$ symmetry. Extending our previous work, where multistate SFDM solutions were shown to form ``gravitational atoms’’ capable of explaining the anisotropic distribution of satellite galaxies (VPOS), we analyze here the coupled dynamics of the scalar and a gauge field at the perturbative level. By solving the perturbed Klein-Gordon and gauge-field equations, we find the temporal evolution and show that the spatial structure of the induced electromagnetic fields is governed by the same spherical Bessel functions and spherical harmonics that characterize the ground and excited states of the multi-state SFDM halo. Remarkably, the presence of the gauge field does not modify the dark-matter density distribution, which preserves the multi-state configuration previously obtained. Our results demonstrate that a charged multi-state SFDM halo can generate coherent, large-scale magnetic fields whose morphology is determined by the excited modes of the scalar field, providing a unified framework in which both galactic magnetic fields and VPOS-like structures originate from the underlying quantum nature of dark matter.

💡 Research Summary

In this paper the authors propose a unified explanation for two long‑standing astrophysical puzzles – the origin of the coherent micro‑gauss magnetic fields observed on kiloparsec scales in galaxies, and the anisotropic distribution of satellite galaxies (the so‑called VPOS) – by invoking a complex scalar‑field dark matter (SFDM) halo that carries a tiny electric charge under a local U(1) symmetry.

The work builds on two earlier ideas. First, a charged SFDM model was introduced in Ref.