Related papers: Vector field and rotational curves in dark galacti…
The specified constant 4-vector field reproducing the spherically symmetric stationary metric of cold dark matter halo in the region of flat rotation curves results in a constant angle of light deflection at small impact distances. The…
The non-gauge vector field with as simple as possible Lagrangian (\ref{Lagrangian}) turned out an adequate tool for macroscopic description of the main properties of dark matter. The dependence of the velocity of a star on the radius of the…
In this work we study rotation curves of spiral galaxies using a model of dark matter based on a scalar-tensor theory of gravity. We show how to estimate the scalar field dark matter parameters using a sample of observed rotation curves.
A mysterious dark matter is supposed to exist in the galactic halos. In this contrast, we discuss the possibility of explaining the flat rotational velocity curves in f(R) gravity by solving field equations numerically in vacuum and for…
We continue to study the spherically symmetric vacuum solutions of the tensor-four-scalars theory which is a modification of general relativity. Our aim is to construct vacuum solutions with asymptotically constant circular velocity curves…
We study static configurations of dark matter coupled to a scalar field responsible for the dark energy of the Universe. The dark matter is modelled as a Fermi gas within the Thomas-Fermi approximation. The mass of the dark matter particles…
We consider weak gravity at accelerations $\alpha<a_H$ when Rindler and cosmological horizon collude at $R_H=c/H$, where $c$ is the velocity of light and $H$ is the Hubble parameter. This is manifest in reduced inertia $m$, below the value…
We show that when the neutrino minimal standard model ($\nu MSM$) with a light sterile neutrino has a long range interaction between the neutrino vacuum charge density and a dark U(1) gauge potential, late time acceleration is dynamically…
In this work, we submit the explanation of spectra of the rotary curves of galaxies on the basis of a vector theory of gravitation without regard to the dark matter hypothesis. We study the approximation of rotary curves in case of existing…
We study a model of vector dark matter with the complex scalar Higgs portal. Renormalisation group equations at the 2-loop level are used to analyse perturbativity and stability of the vacuum. We impose experimental and theoretical…
Recently, a new alternative vector theory of gravity has been proposed which assumes that universe has fixed background Euclidean geometry and gravity is a vector field that alters this geometry [Phys. Scr. 92, 125001 (2017)]. It has been…
We investigate, in the framework of a recently introduced new class of invariant geometrical scalar-tensor theory of gravity, the possibility that a viscous dark fluid can be described in a unified manner by a single scalar field. Thus we…
Galaxy rotation curves determined observationally out to a radius well beyond the galaxy cores can provide a critical test of modified gravity models without dark matter. The predicted rotational velocity curve obtained from…
We investigate the static and spherically symmetric solutions of Einstein's equations for a scalar field with non-canonical kinetic term, assumed to provide both the dark matter and dark energy components of the Universe. In particular, we…
As galactic halos are not directly visible, there are many ambiguities regarding their composition and rotational velocity. Though most of the dark matter is non-baryonic, {\it some fraction is}, and it can be used to trace the halo…
We analyze the local field of stellar tangential velocities for a sample of $42 339$ non-binary Hipparcos stars with accurate parallaxes, using a vector spherical harmonic formalism. We derive simple relations between the parameters of the…
Knowledge of the shape of dark matter halos is critical to our understanding of galaxy formation, dynamics, and of the nature of dark matter itself. Polar ring galaxies (PRGs) --- early-type galaxies defined by their outer rings of gas,…
As an alternative to dark matter models we use generalized Jordan-Brans-Dicke scalar-vector-tensor (JBD-SVT) gravity model to study the behavior of the rotational velocities of test particles moving around galaxies. To do so we consider an…
As a candidate for dark matter in galaxies, we study an SU(3) triplet of complex scalar fields which are non-minimally coupled to gravity. In the spherically symmetric static spacetime where the flat rotational velocity curves of stars in…
We revisit the issue of the constancy of the dark matter (DM) and baryonic Newtonian acceleration scales within the DM scale radius by considering a large sample of late - type galaxies. We rely on a Markov Chain Monte Carlo (MCMC) method…