Relativistic compact stars with charged anisotropic matter

In this article, we perform a detailed theoretical analysis of new exact solutions with anisotropic fluid distribution of matter for compact objects subject to hydrostatic equilibrium. We present a family solution to the Einstein-Maxwell equations describing a spherically symmetric, static distribution of a fluid with pressure anisotropy. We implement an embedding class one condition to obtain a relation between the metric functions. We generalize the properties of a spherical star with hydrostatic equilibrium using the generalised Tolman-Oppenheimer-Volkoff (TOV) equation. We match the interior solution to an exterior Reissner-Nordström one, and study the energy conditions, speed of sound, and mass-radius relation of the star. We also show that the obtained solutions are compatible with observational data for the compact object Her X-1. Regarding our results, the physical behaviour of the present model may serve for the modeling of ultra compact objects.     

Noether symmetry in the Nash theory of gravity

This paper deals with the study of Bianchi type-I universe in the context of Nash gravity by using the Noether symmetry approach. We shortly revisit the Nash theory of gravity. We make a short recap of the Noether symmetry approach and consider the geometry for Bianchi-type I model. We obtain the exact general solutions of the theory inherently exhibited by the Noether symmetry. We also examine the cosmological implications of the model by discussing the two cases of viable scenarios. Surprisingly, we find that the predictions are nicely compatible with those of the \(\Lambda \)CDM model.     

Gravitational Lensing by Traversable Wormholes Supported by Three-Form Fields

In this paper, the deflection angle of light by traversable wormholes, which are supported by the three-form fields, are studied. The specific forms of the redshift and shape functions that produce results compatible with the energy conditions at throat of the wormholes are used. Having used the well-defined parameter sets of the three-form wormholes, the photon geodesic motion is investigated under the effective potential of the wormhole background. As a result, it is discovered that the radius of the photon sphere can be used to analyze the geometrical structures of a physical wormhole. The analytical form of the effective potential is used to figure out a deflection angle of light caused by wormholes with the three-from fields. In this work, the relativistic images generated from the wormholes are also constructed.