In the weak field approximation, the nonsymmetric gravitational theory (NGT) has, in addition to the Newtonian gravitational potential, a Yukawalike potential produced by the exchange of a spin 1+ boson between fermions. If the range r0 = μ −1 is 25 kpc, then this additional potential due to the interaction with matter in the halos of galaxies can explain the flat rotation curves of galaxies an...

The nature of the gravitational interaction between ordinary and dark matter is still open, and deviations from universality or Newtonian law may also modify the standard assumption of collisionless dark matter. On the other hand, obtaining a Yukawa-like large-distance modification of the gravitational potential is a nontrivial problem, that has so far eluded a consistent realization even at li...

We consider the possibility that masses and gravitational potentials of galaxy cluster, estimated at X-ray wavelengths, could be explained without assuming huge amounts of dark matter, but in the context of f(R)-gravity. Specifically, we take into account the weak field limit of such theories and show that the corrected gravitational potential allows to estimate the total mass of a sample of 12...

Deviations from the 1/r 2 Newton law due to extra dimensions and α ′-corrections Abstract We systematically examine corrections to the gravitational inverse square law, which are due to compactified extra dimensions, and to higher-derivative R 2-terms in the effective gravitational action. We find that both induce Yukawa-type potentials for which we calculate the strength α and range. In genera...

We present a method for recovering the distribution functions of edge-on thin axisymmetric disks directly from their observable kinematic properties. The most generally observable properties of such a stellar system are the line-of-sight velocity distributions of the stars at different projected radii along the galaxy. If the gravitational potential is known, then the general two-integral distr...

We systematically examine corrections to the gravitational inverse square law, which are due to compactified extra dimensions, and to higher-derivative R 2-terms in the effective gravitational action. We find that both induce Yukawa-type potentials for which we calculate the strength α and range. In general the range of the Yukawa correction is given by the wavelength of the lightest Kaluza–Kle...

This paper revisits the concept of specific resistance, a dimensionless measure of locomotive efficiency often used to compare the transport cost of vehicles (Gabrielli & von Karman 1950), and extends its use to the vertical domain. As specific resistance is designed for comparing horizontal locomotion, we introduce a compensation term in order to offset the gravitational potential gained or lo...

The effect of gravitational lensing on cosmic microwave background (CMB) anisotropies is investigated using the power spectrum approach. The lensing effect can be calculated in any cosmological model by specifying the evolution of gravitational potential. Previous work on this subject is generalized to a non-flat universe and to a nonlinear evolution regime. Gravitational lensing cannot change ...

Multidimensional cosmological models with factorizable geometry and their dimensional reduction to effective four-dimensional theories are analyzed on sensitivity to different scalings. It is shown that a noncorrect gauging of the effective four-dimensional gravitational constant within the dimensional reduction results in a non-correct rescaling of the cosmological constant and the gravexciton...

Finite-temperature spectra of heavy quarkonia are calculated by combining potential model and thermofield dynamics formalisms. The mass spectra of the heavy quarkonia with various quark contents are calculated. It is found that binding mass of the quarkonium decreases as temperature increases.a Quarkonia; finite-temperature spectra; thernofield dynamics.