Related papers: A three-layer preon star model from exact piecewis…
The equation of state provided by effective models of strongly interacting matter should comply with the restrictions imposed by current astrophysical observations on compact stars. Using the equation of state given by the (axial-)vector…
We find constraints on minimum and maximum mass of ordinary neutron stars imposed by their early evolution (protoneutron star stage). We calculate models of protoneutron stars using a realistic standard equation of state of hot, dense…
We analyze the observed properties of dwarf galaxies, which are dark matter dominated astrophysical objects, by assuming that dark matter is in the form of a strongly - coupled, dilute Bose - Einstein condensate. The basic astrophysical…
The equation of state inside very compact objects like neutron stars is still largely unkown. Even though a lot progress has been made in recent years to develop the so-called realistic equations of state, a lot of insight can be gained by…
The present work represents a step to deal with stellar structure using a pure geometric approach. A geometric field theory is used to construct a model for a spherically symmetric configuration. The model obtained can be considered as a…
The linear chiral SU(3)*SU(3) model is applied to describe properties of the compact star matter inside the quark, protoneutron and neutron star.The leads to the neutron star with the value of maximum mass close to 1.5 solar mass and radius…
We study the structure of neutron stars in $f(R)=R+\alpha R^{2}$ theory of gravity (Starobinsky model), in an exact and non-perturbative approach. In this model, apart from the standard General Relativistic junction conditions, two extra…
We consider the sector of Horndeski's gravity characterized by the coupling between the kinetic scalar field term and the Einstein tensor. We numerically construct neutron star configurations where the external geometry is identical to the…
We present new, fully nonlinear numerical solutions to the static, spherically symmetric Einstein-Klein-Gordon system for a collection of an arbitrary odd number $N$ of complex scalar fields with an internal $U(N)$ symmetry and no…
A self-consistent electrodynamics of a particle accelerator in a rotating neutron-star magnetosphere is investigated on the two-dimensional poloidal plane. Solving the Poisson equation for the electrostatic potential together with the…
We construct exact static inhomogeneous solutions to Einstein's equations with counter flow of particle fluid and a positive cosmological constant by using the Sasaki metrics on three-dimensional spaces. The solutions, which admit an…
An approximate analytic one-dimensional model is constructed, for the accretion disk boundary layer surrounding a neutron star whose low magnetic field does not affect the process of accretion. A high luminosity model is considered, with…
The general solution of hydrostatic equilibrium equations for a two-component fluid of ions and electrons without a local electroneutrality constraint is found in the framework of Newtonian gravity theory. In agreement with the Poincar\'e…
According to the braneworld idea, ordinary matter is confined on a 3-dimensional space (brane) that is embedded in a higher-dimensional space-time where gravity propagates. In this work, after reviewing the limits coming from general…
Formed in the aftermath of gravitational core-collapse supernova explosions, neutron stars are unique cosmic laboratories for probing the properties of matter under extreme conditions that cannot be reproduced in terrestrial laboratories.…
We develop a method for constructing exact cosmological solutions of the Einstein equations based on representing them as a second-order linear differential equation. In particular, the method allows using an arbitrary known solution to…
We explore the possibility of three phases in the core of neutron star in a form of triple layers. From the center, strange quark matter, kaon condensed nuclear matter and nuclear matter form a triple layer. We discuss how the phase of…
We investigate the equation of state(EoS) and the effect of the hadron-quark phase transition of strong interaction matter in compact stars. The hadron matter is described with the relativistic mean field theory,and the quark matter is…
Neutron star matter is investigated in a hadronic chiral model approach using the lowest flavor-SU(3) multiplets for baryons and mesons. The parameters are determined to yield consistent results for saturated nuclear matter as well as for…
We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…