Abstract
The idea of ultralight scalar (axion) dark matter is theoretically appealing
and may resolve some small-scale problems of cold dark matter; so it deserves
careful attention. In this work we carefully analyze tunneling of the scalar
field in dwarf satellites due to the tidal gravitational force from the host
halo. The tidal force is far from spherically symmetric; causing tunneling
along the axis from the halo center to the dwarf, while confining in the
orthogonal plane. We decompose the wave function into a spherical term plus
higher harmonics, integrate out angles, and then numerically solve a residual
radial Schrödinger-Poisson system. By demanding that the core of the Fornax
dwarf halo can survive for at least the age of the universe places a bound on
the dark matter particle mass $210^-22\,eVmłesssim
610^-22\,$eV. Interestingly, we show that if another very low density
halo is seen, then it rules out the ultralight scalar as core proposal
completely. Furthermore, the non-condensed particles likely impose an even
sharper lower bound. We also determine how the residual satellites could be
distributed as a function of radius.
Users
Please
log in to take part in the discussion (add own reviews or comments).