On dark stars, Planck cores and the nature of dark matter

Abstract

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 ∼ 10 49 and the emission wavelength λ 0 ∼ 10 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 ρ ∼ 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 λ ∼ 1m 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.

Galactic model with a phase transition from dark matter to dark energy

“…This work continues the construction of the model [1] presented at Bled 2020 Workshop "What Comes Beyond the Standard Models?". In this model, the sources of dark matter are Planck cores, Planck density objects located inside black holes.…”

“…A more accurate estimate is obtained from the fit of the MW rotation curve, the so-called Grand Rotation Curve (GRC, [44][45][46][47][48]). From this fit it can be seen, [1] Fig. 2, that on an approximately flat portion of the rotation curve at the position of the Sun r ∼ 8kpc there is a significant contribution of luminous matter, as a result of which the contribution of dark matter to v 2 is less than the trivial estimate.…”

“…The model [1] considers three cases: massive, null or tachyon radial dark matter (M/N/T-RDM). The tachyon case is too exotic and will not be considered here.…”

“…In relation to the -parameter for the Milky Way (MW) galaxy, [1] provides several estimates. The simplest, if one places a single RDM star in the center of the galaxy and completely neglect the contribution of the luminous matter, leads to a flat rotation curve with an orbital velocity v ∼ 200km/s, = (v/c) 2 ∼ 4 • 10 −7 .…”

“…Further, with increasing radius, the contribution of luminous matter decreases, while the contribution of dark matter remains constant up to R cut ∼ 50kpc. This contribution corresponds to the galactic = M dm (R cut )/R cut , in geometric units, being averaged over the scenarios considered in [1]:…”