On dark stars, Planck cores and the nature of dark matter
  Dark stars are compact massive objects, described by Einstein gravitational
field equations with matter. The type we consider possesses no event horizon,
instead, there is a deep gravitational well with a very strong redshift factor.
Observationally, dark stars can be identified with black holes. Inside dark
stars, Planck density of matter is reached, Planck cores are formed, where the
equations are modified by quantum gravity. In the paper, several models of dark
stars with Planck cores are considered, resulting in the following hypothesis
on the composition of dark matter. The galaxies are flooded with low-energetic
radiation from the dark stars. The particle type can be photons and gravitons
from the Standard Model, can also be a new type of massless particles. The
model estimations show that the extremely large redshift factor $z\sim10^{49}$
and the emission wavelength $\lambda_0\sim10^{14}$m can be reached. The
particles are not registered directly in the existing dark matter experiments.
They come in a density sufficient to explain the observable rotation curves.
The emission has a geometric dependence of density on radius $\rho\sim r^{-2}$,
producing flat rotation curves. The distribution of sources also describes the
deviations from the flat shape. The model provides a good fit of experimental
rotation curves. Outbreaks caused by a fall of an external object on a dark
star lead to emission wavelength shifted towards smaller values. The model
estimations give the outbreak wavelength $\lambda\sim1$m compatible with fast
radio bursts. The paper raises several principal questions. White holes with
Planck core appear to be stable. Galactic rotation curves in the considered
setup do not depend on the matter type. Inside the galaxy, dark matter can be
of hot radial type. At cosmological distances, it can behave like the cold
uniform type.
