相关论文: Compact Stars Sourced by Perfect Fluid Dark Matter…

We investigate the shadow of an exact black hole solution of Einstein's equations recently proposed by Cardoso et al., to describe a supermassive black hole immersed in a dark matter halo. We analyze and discuss the light rings and the…

Dark matter and dark energy dominate the behavior of our universe. The dark matter usually forms halo structures in large number of galaxies. Properties of dark matter halo can be revealed and understood from the gravitational lensing…

Concerning the stability of two-fluid star models, we prove the rigorous equivalence of two independent determining methods for mixed stars, after a brief review of the hybrid star case. Our derivations apply to general multi-fluid cases,…

We consider simple hydrodynamical models of galactic dark matter in which the galactic halo is a self-gravitating and self-interacting gas that dominates the dynamics of the galaxy. Modeling this halo as a sphericaly symmetric and static…

A simple gravitational model with torsion is studied, and it is suggested that it could explain the dark matter and dark energy in the universe. It can be reinterpreted as a model using the Einstein gravitational equations where spacetime…

In this work we model galactic halos describing the dark matter as a non zero pressure fluid and derive, not impose, a dark matter equation of state by using observational data of the rotation curves of galaxies. In order to reach…

The hybrid Ricci scalar $R_{\mu\nu}\eta^{\mu\nu}$ formed from a Robertson-Walker derived Ricci tensor and a distinct flat space metric becomes a dark, pseudo-isothermal density under asymptotic constraint. While extension of this constraint…

We develop a new model for a spherically symmetric dark matter fluid sphere containing two regions: {\bf (i)} Isotropic inner region with constant density and {\bf (ii)} Anisotropic outer region. We solve the system of field equation by…

We consider the contribution of neutron stars and black holes to the dynamical mass of galactic halos. In particular, we show that if these compact objects were produced by an early generation of stars with initial metallicity less than…

Theoretical results on a conventional approach to the dark energy (DE) concept are reviewed and discussed. According to them, there is absolutely no need for a novel DE component in the Universe, provided that the associated matter-energy…

After deducing the density profiles and gravitational potential functions of eight galaxies from the rotation velocity data from THINGS, we find that the density decreases exponentially with the potential in substantial regions of the…

This paper discusses a new model for galactic dark matter by combining an anisotropic pressure field corresponding to normal matter and a quintessence dark energy field having a characteristic parameter $\omega_q$ such that $-1<\omega_q<…

A halo model is presented which possesses a constant phase space density (Q) core followed by a radial CDM-like power law decrease in Q. The motivation for the core is the allowance for a possible primordial phase space density limit such…

We present new anisotropic generalization of Buchdahl [1] type perfect fluid solution by using the method of earlier work [2]. In similar approach we have constructed the new pressure anisotropy factor ${\Delta}$ by the help both the metric…

We investigate whether a dark matter with substantial amounts of pressure, comparable in magnitude to the energy density, could be a viable candidate for the constituent of dark matter halos. We find that galaxy halos models, consistent…

The Einstein-Maxwell (or Einstein) system of field equations plays a substantial role in the modeling of compact stars. Although due to its non-linearity getting an exact solution for the system of field equations is a difficult task, the…

We present a class of exact solutions of Einstein's gravitational field equations describing spherically symmetric and static anisotropic stellar type configurations. The solutions are obtained by assuming a particular form of the…

In the present paper we develop an algorithm for all spherically symmetric anisotropic charged fluid distribution. Considering a new source function $\nu(r)$ we find out a set of solutions which is physically well behaved and represent…

A new solution for the endpoint of gravitational collapse is proposed. By extending the concept of Bose-Einstein condensation to gravitational systems, a cold, compact object with an interior de Sitter condensate phase and an exterior…

Asymmetric dark matter under certain conditions could form compact star-like objects, which can be searched either through gravitational lensing or by observation of gravitational waves from binaries involving such compact objects. In this…