Numerical solutions of Einstein field equations with radial dark matter

Klimenko, Stanislav; Nikitin, Igor; Nikitina, Lialia

doi:10.1142/s0129183117500966

Cited by 11 publications

(54 citation statements)

References 27 publications

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“…A recent advance has been reported by Holdom and Ren in their paper "Not quite a black hole" [2]. Our contribution to this family are RDM-stars [3], quasi black holes coupled to Radial Dark Matter. A typical configuration of an RDM-star is shown on Fig.…”

Section: Introductionmentioning

confidence: 67%

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

Nikitin¹

2021

Preprint

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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.

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Section: Introductionmentioning

confidence: 67%

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

Nikitin¹

2021

Preprint

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“…As a suitable environment, we use the model of null radial dark matter (NRDM, [41]). This model considers a static spherically symmetric distribution of dark matter, described by a perfect fluid EOS of the form ρ = p r , p t = 0.…”

Section: Opening Wormholesmentioning

confidence: 99%

“…In the central region of this solution, the redshift A-profile rapidly drops with a decreasing radius. In [41] such behavior was called red supershift. It is closely related to the mass inflation phenomenon found in a black hole model with counterstreaming matter flows [42].…”

Section: Opening Wormholesmentioning

confidence: 99%

“…Coordinate transformations are applied to display conveniently different scales of (A, B, Z, W, r) functions. While [41] used logarithmic transformations:…”

Section: Opening Wormholesmentioning

confidence: 99%

“…The NRDM model is used in [41] to represent the galactic dark matter distribution and the related rotation curves. In the single center approximation, where the dark matter distribution is related with the central black hole, the model provides flat rotation curves with the scaling parameter = (v/c) 2 .…”

Section: Opening Wormholesmentioning

confidence: 99%

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Wormholes and Teleporters

Nikitin

2021

Preprint

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In general relativity, there is a class of solutions that currently do not have observed analogues, but on which the theory is shaped, giving an understanding what is fundamentally possible within its framework. Such solutions include wormholes, tunnels that connect distant regions in spacetime. Although not a single wormhole has yet been discovered, there is a large number of works devoted to their study, thanks to which wormholes as a class of solutions become firmly established in modern science. In this paper, we consider two topologically nontrivial types of solutions related to wormholes. First: wormholes that can open and close. In this relation, we will discuss topological censorship theorems, which under certain conditions prohibit changing topology. We will also discuss known ways to circumvent these theorems. Using analytical and numerical methods, as well as visualization, we will construct an example of an opening and closing wormhole with the dimensions of the central black hole in the Milky Way galaxy. Our construction continues the work by Kardashev, Novikov and Shatskiy, in which a static wormhole with the same parameters was considered. The second type is a modification of Visser's dihedral wormhole solution for a dynamic case, which can be considered as a model of a teleportation event.

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Shadow and weak deflection angle of extended uncertainty principle black hole surrounded with dark matter

Pantig

Rodulfo

et al. 2022

Annals of Physics

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Numerical solutions of Einstein field equations with radial dark matter

Cited by 11 publications

References 27 publications

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

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

Wormholes and Teleporters

Shadow and weak deflection angle of extended uncertainty principle black hole surrounded with dark matter

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