In this article, we present an example of inhomogeneous cosmological model, which is inspired by the linear perturbation theory. The metric model can be described as Einstein--de Sitter background with periodically distributed dust overdensities. construction enables application Green-Wald averaging scheme and Buchert technique simultaneously. We compare angular diameter distance function considered to distances corresponding average space-times given frameworks respectively.

The aim of this work is to show, in the framework a simple finite-width disk model, that amount mass seen through gravitational microlensing measurements region 0 < R R° consistent with dynamical ascertained from Galaxy rotation after subtracting gas contribution. Since only detects compact objects, result suggests non-baryonic component may be negligible region.

Abstract Recently, we constructed the specific solution to second-order cosmological perturbation theory, around any Friedmann–Lemaître–Robertson–Walker background filled with dust matter and a positive constant. In this paper, use Cosmicflows-4 sample of galaxies from Extragalactic Distance Database constrain metric tensor. We obtain an approximation local distribution geometry. numerically solve for null geodesics randomly distributed mock sources compare model Lemaître–Hubble constant...

In this paper we model the vertical structure of mass distribution Milky Way galaxy in framework a finite-width global disk model. Assuming Galactic rotation curve only, test inside solar orbit predictions for two measurable and unrelated to each other processes: gravitational microlensing that allows fix width-scale by best fit measurements, gradient modelled quasi-circular orbits approximation. The former is sensitive gravitating compact objects latter all kinds matter. analysis points...

The main aim of this project was to design and construct the laboratory setup perform testing ABS car systems. In paper a realistic brake system for one wheel with suspension is used. Development implementation architecture integrated real-time, embedded control software described. At same time, it includes an exploratory study dynamics model, monitor sensor system, etc. at graphical programming level then established. addition, provides rapid prototyping in based on MPC Target has strong...

We constructed a simple cosmological model which approximates the Einstein-de Sitter background with periodically distributed dust inhomogeneities. By taking metric as power series up to third order in some perturbative parameter $\ensuremath{\lambda}$, we are able achieve large values of density contrast. With explicitly given, many properties can be calculated straightforward way is interesting context current discussion concerning averaging inhomogeneities and their backreaction...

Abstract We construct an approximate solution to the cosmological perturbation theory around Einstein–de Sitter background up fourth-order perturbations. This could be done with help of specific symmetry condition imposed on metric, from which follows that model density forms infinite, cubic lattice. To verify convergence perturbative construction, we express resulting metric as a polynomial in parameter and calculate exact Einstein tensor. In our model, it seems physical quantities averaged...

We model the phase-space distribution of kinematic tracers using general, smooth functions to derive a conservative lower bound on total mass within ≈150−200 kpc. By approximating potential as Keplerian, can be simplified that energies and eccentricities. Our approach naturally allows for calculating moments function, such radial profile orbital anisotropy. systematically construct family with resulting velocity dispersion overlapping one obtained data motions distant tracers, while making...

Observations suggest a slower stellar rotation relative to gas in the outer part of Milky Way Galaxy. This difference could be attributed an interaction with interstellar magnetic field. In simple model, fields order 10 micro Gauss are then required, consistently observed values. coincidence suggests tool for estimating spiral galaxies. A North-South asymmetry Galaxy origin too.

Ring mass density and the corresponding circular velocity in thin disk model are known to be integral transforms of one another. But it may less familiar that can reduced one-fold integrals with identical weight functions. It practical value for surface does not involve derivative, unlike equivalent widely Toomre's formula.

We use a cosmological counterpart of the cylindrical Halilsoy solution to illustrate properties cross-polarized standing gravitational waves.Received 3 September 2022Accepted 28 November 2022DOI:https://doi.org/10.1103/PhysRevD.106.124022© 2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasGeneral relativityGravitational wavesGravitation, Cosmology & Astrophysics

In this paper, a specific solution to the second-order cosmological perturbation theory is given. Perturbations are performed around any FLRW spacetime filled with dust and positive constant. particular, possibly non-vanishing spatial curvature. The adopted symmetry condition allows us simplify equations, leaving great deal of freedom choose density distribution. result, we get relatively simple metric an inhomogeneous model, which will give perfect tool for studying influence local...

Recently, we determined a lower bound for the Milky Way mass in point approximation. We obtain this result most general spherically symmetric phase-space distribution functions consistent with measured radial velocity dispersion. As stability test of these predictions against perturbation potential, paper make use representative to set initial conditions simulation more realistic potential similar and account other observations. The predicted dispersion profile evolves forms still profile,...

The behavior of an atomic electron in a static magnetic field strong enough to correspond the transition regime is examined. strength characterized by parameter L^, effective component angular momentum. A Floquet-Mathieu analysis shows that bifurcation classical trajectories into elliptical and helical families related 2:1 resonance which occurs at L^=L${^}_{T}$. Quantum mechanics gives avoided crossing L${^}_{T}$; we examine nature wave functions as L^ passes through resonance....

We study the vertical gradient in azimuthal velocity of spiral galaxy NGC 4244 a thin disk model. With surface density accounting for rotation curve, we model properties approximation quasi-circular orbits and find predictions to be consistent with inferred from measurements. This consistency may suggest that mass distribution this is flattened.

Within the disk model framework used to approximately describe flattened galaxies, we develop an iterative method of determining column mass density from rotation curve supplemented with isotropic velocity dispersion profile. This generalizes our previous case when becomes important. We show on example UGC 6446 galaxy, that taking into account results in some observational signatures behavior local mass-to-light ratio. Along galactic magnetic fields, this is another factor allowing...

Taking the velocity dispersion term into account in Jeans equation describing disk model, counterintuitively allows to reduce local mass-to-light ratio at outskirts of flattened galaxies, and stop unbound growth mass function.This is possible thanks a more intertwined relation between gravitational potential rotation curve than for spheroidal systems.This effect illustrated on example galaxy UGC 6446 by finding iteratively column density from supplemented with an isotropic profile...