16 citations · 61 across the 14 of their papers we have counts for
14 papers
The model of the local Universe in the framework of the second-order perturbation theory
Szymon Sikora, Jan J. Ostrowski
Recently, we constructed the specific solution to the second-order cosmological perturbation theory, around any Friedmann-Lemaitre-Robertson-Walker (FLRW) background filled with du…
Second-order dust perturbations of the non-flat FLRW model with the positive cosmological constant
Szymon Sikora
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 with a…
Example of cross-polarized standing gravitational waves
Krzysztof Głód, Szymon Sikora, Sebastian J. Szybka
We use a cosmological counterpart of the cylindrical Halilsoy solution to illustrate properties of cross-polarized standing gravitational waves.
Construction of the cosmological model with periodically distributed inhomogeneities with growing amplitude
Szymon Sikora, Krzysztof Głód
We construct an approximate solution to the cosmological perturbation theory around Einstein-de Sitter background up to the fourth-order perturbations. This could be done with the…
Perturbatively constructed cosmological model with periodically distributed dust inhomogeneities
Szymon Sikora, Krzysztof Głód
We constructed a simple cosmological model which approximates the Einstein-de Sitter background with periodically distributed dust inhomogeneities. By taking the metric as a power…
Example of an inhomogeneous cosmological model in the context of backreaction
Szymon Sikora, Krzysztof Głód
In this article, we present an example of an inhomogeneous cosmological model, which is inspired by the linear perturbation theory. The metric of this model can be described as the…
Magnetic flux density from the relative circular motion of stars and partially ionized gas in the Galaxy mid-plane vicinity
Joanna Jałocha, Łukasz Bratek, Jan Pękala +2
Observations suggest a slower stellar rotation relative to gas rotation in the outer part of the Milky Way Galaxy. This difference could be attributed to an interaction with the in…
Velocity dispersion as a factor modifying the distribution of mass in disk-like galaxies -- an example of galaxy UGC 6446
Szymon Sikora, Łukasz Bratek, Joanna Jałocha +1
Within the disk model framework used to approximately describe flattened galaxies, we develop an iterative method of determining column mass density from rotation curve supplemente…
Modeling vertical structure in circular velocity of spiral galaxy NGC 4244
Joanna Jałocha, Łukasz Bratek, Szymon Sikora +1
We study the vertical gradient in azimuthal velocity of spiral galaxy NGC 4244 in a thin disk model. With surface density accounting for the rotation curve, we model the gradient p…
Velocity-density twin transforms in thin disk model
Łukasz Bratek, Szymon Sikora, Joanna Jałocha +1
Ring mass density and the corresponding circular velocity in thin disk model are known to be integral transforms of one another. But it may be less familiar that the transforms can…
Motion of halo compact objects in the gravitational potential of a low-mass model of the Galaxy
Szymon Sikora, Łukasz Bratek, Joanna Jałocha +1
Recently, we determined a lower bound for the Milky Way mass in a point mass approximation. This result was obtained for most general spherically symmetric phase-space distribution…
Constraining the vertical structure of the Milky Way rotation by microlensing in a finite-width global disk model
Joanna Jałocha, Szymon Sikora, Łukasz Bratek +1
In this paper we model the vertical structure of mass distribution of the Milky Way galaxy in the framework of a finite-width global disk model. Assuming the Galactic rotation curv…
A lower bound on the Milky Way mass from general phase-space distribution function models
Łukasz Bratek, Szymon Sikora, Joanna Jałocha +1
We model the phase-space of the kinematic tracers using general, smooth distribution functions to derive a conservative lower bound on the total mass within 150-200 kpc. By approxi…
Gravitational microlensing as a test of a finite-width disk model of the Galaxy
Szymon Sikora, Łukasz Bratek, Joanna Jałocha +1
The aim of this work is to show, in the framework of a simple finite-width disk model, that the amount of mass seen through gravitational microlensing measurements in the region $0…