Narrow Results

We study the dipolar magnetic field configuration and present solutions of Maxwell equations in the internal background spacetime of a slowly rotating gravastar. The shell of gravastar where magnetic field penetrated is modeled as sphere consisting of perfect highly magnetized fluid with infinite conductivity. Dipolar magnetic field of the gravastar is produced by a circular current loop symmetrically placed at radius a at the equatorial plane.

We study magnetic field effects on the Equations-of-State (EoS) and the structure of Bose–Einstein Condensate (BEC) stars, i.e. a compact object composed by a gas of interacting spin-one bosons formed up by the pairing of two neutrons. To include the magnetic field in the thermodynamic description, we assume that particle–magnetic field and particle–particle interactions are independent. We consider two configurations for the magnetic field: one where it is constant and externally fixed, and another where it is produced by the bosons through self-magnetization. Stable configurations of self-magnetized and magnetized nonspherical BEC stars are studied using structure equations that describe axially symmetric objects. In general, the magnetized BEC stars are spheroidal, less massive and smaller than the nonmagnetic ones, being these effects more relevant at low densities. Nevertheless, star masses around two solar masses are obtained by increasing the strength of the boson–boson interaction. The inner magnetic field profiles of the self-magnetized BEC stars can be computed as a function of the equatorial radii. The values obtained for the core and surface magnetic fields are in agreement with those typically found in compact objects.

We investigate the interior Einstein’s equations in the case of a static, axially symmetric, perfect fluid source. We present a particular line element that is specially suitable for the investigation of this type of interior gravitational fields. Assuming that the deviation from spherically symmetry is small, we linearize the corresponding line element and field equations and find several classes of vacuum and perfect fluid solutions. We find some particular approximate solutions by imposing appropriate matching conditions.

We present a model of compact astrophysical object under General Theory of Relativity using the anisotropic extension of Tolman IV solution. The anisotropy function, derived from the model, remains well behaved throughout the interior of the star. The model satisfies several necessary conditions for a physically realistic compact star. Physical viability of the model is verified specifically by plugging in the estimated parameter values of the Low Mass X-ray Binary (LMXB) candidate 4U 1608–52. Our stability analysis of this star, by using various criteria for stability, provides satisfactory results. In connection to anisotropy, we compute the Tidal Love Number (TLN) for the compact stellar model and compare the calculated values with existing literature.

We study in the weak field limit the gravitational lensing by spherically symmetric compact object immersed in an asymptotically uniform magnetic field in the presence of plasma and our approach is based on the medium modified Hamiltonian one. We show that the magnetized plasma in the environment of compact object may lead to split of the Einstein cross, creating additional lensed components. Finally we calculate magnification and time delay related to the individual images.