Optical properties of Einstein–Born–Infeld gravastar models in plasmas

Gravastar models have recently been proposed as an alternative to black holes, mainly to avoid the problematic issues associated with event horizons and singularities. Recently, in [D. J. Cirilo-Lombardo and C. D. Vigh, Int. J. Mod. Phys. D 28 (2019) 1950108], a regular variety of gravastar models within the context of Einstein–Born–Infeld (EBI) nonlinear electrodynamics were built. These original models are truly regular in the sense that both the metric and its derivatives are continuous throughout spacetime, contrary to other cases in the literature where matching conditions are necessary in the interior and exterior regions of the event horizon. In this work, in the same theoretical context from [D. J. Cirilo-Lombardo and C. D. Vigh, Int. J. Mod. Phys. D 28 (2019) 1950108], we study some optical phenomena, such as the weak gravitational lens for the case of the magnetized plasma and the influence of working with a nonlinear field of BI in observables such as the Einstein ring or the total delay time. These important issues allow us to compare the results obtained in the context of these new static Born–Infeld gravastars with the standard linear ones (e.g. Reissner–Nordström).

Download Full-text

Einstein–Born–Infeld gravastar models, dark matter and accretion mechanisms

International Journal of Modern Physics D ◽

10.1142/s0218271819501086 ◽

2019 ◽

Vol 28 (08) ◽

pp. 1950108 ◽

Cited By ~ 1

Author(s):

D. J. Cirilo-Lombardo ◽

C. D. Vigh

Keyword(s):

Momentum Tensor ◽

Rate Of Change ◽

Nonlinear Electrodynamics ◽

Anisotropic Fluid ◽

Spherically Symmetric ◽

Regular Variety ◽

Accretion Process ◽

Accretion Rates ◽

Exterior Regions ◽

Spherically Symmetric Metric

Gravastar models have recently been proposed as an alternative to black holes, mainly to avoid the problematic issues associated with event horizons and singularities. In this work, a regular variety of gravastar models within the context of Einstein–Born–Infeld (EBI) nonlinear electrodynamics are builded. These models presented here are truly regular in the sense that both the metric and its derivatives are continuous throughout spacetime, contrary to other cases in the literature where matching conditions are necessary in the interior and exterior regions of the event horizon. We investigated the accretion process for spherically symmetric spacetime geometries generated for a nonlinear electromagnetic field where the energy–momentum tensor has the same form that an anisotropic fluid that is the general EBI case. We analyze this procedure using the most general static spherically symmetric metric ansatz. In this theoretical context, we examined the accretion process for specific spherically symmetric compact configuration obtaining the accretion rates and the accretion velocities during the process and the flow of the fluid around the black hole. In addition, we study the behavior of the rate of change of the mass for each chosen metric.

Download Full-text

Magnetized filament models for diverging plasma lenses

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa360 ◽

2020 ◽

Vol 493 (2) ◽

pp. 1736-1752

Author(s):

Adam Rogers ◽

Abdul Mohamed ◽

Bailey Preston ◽

Jason D Fiege ◽

Xinzhong Er

Keyword(s):

Magnetic Field ◽

Column Density ◽

Volume Density ◽

Magnetized Plasma ◽

Gravitational Lens ◽

Line Of Sight ◽

Density Distributions ◽

Rotation Measure ◽

Spherical Plasma ◽

Helical Magnetic Field

ABSTRACT Spherical plasma lens models are known to suffer from a severe overpressure problem, with some observations requiring lenses with central pressures up to millions of times in excess of the ambient interstellar medium. There are two ways that lens models can solve the overpressure problem: a confinement mechanism exists to counter the internal pressure of the lens, or the lens has a unique geometry, such that the projected column-density appears large to an observer. This occurs with highly asymmetric models, such as edge-on sheets or filaments, with potentially low volume–density. In the first part of this work we investigate the ability of non-magnetized plasma filaments to mimic the magnification of sources seen behind spherical lenses and we extend a theorem from gravitational lens studies regarding this model degeneracy. We find that for plasma lenses, the theorem produces unphysical charge density distributions. In the second part of the work, we consider the plasma lens overpressure problem. Using magnetohydrodynamics, we develop a non self-gravitating model filament confined by a helical magnetic field. We use toy models in the force-free limit to illustrate novel lensing properties. Generally, magnetized filaments may act as lenses in any orientation with respect to the observer, with the most high-density events produced from filaments with axes near the line of sight. We focus on filaments that are perpendicular to the line of sight that show the toroidal magnetic field component may be observed via the lens rotation measure.

Download Full-text

Induced gravitation in nonlinear field models

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194516601198 ◽

2016 ◽

Vol 41 ◽

pp. 1660119 ◽

Cited By ~ 2

Author(s):

Alexander A. Chernitskii

Keyword(s):

Field Model ◽

Gravitational Interaction ◽

Specific Form ◽

Nonlinear Electrodynamics ◽

Soliton Interaction ◽

Nonlinear Field ◽

Range Interaction ◽

Force Interaction ◽

Long Range Interaction ◽

Interaction Of Solitons

The description of gravitation in the framework of soliton interaction is considered for two nonlinear field models. These models are Born — Infeld nonlinear electrodynamics and so-called Born — Infeld type scalar field model. The last model can also be called the extremal space-time film one because of the specific form of the appropriate variational principle. Gravitational interaction is considered in the context of unification for all interactions of material particles. It is shown that long-range interaction of solitons of the models appears as force one and metrical one. The force interaction can be interpreted as electromagnetic one. The metrical interaction can be interpreted as gravitational one.

Download Full-text

Fundamental interactions and quantum behavior in unified field theory

International Journal of Modern Physics A ◽

10.1142/s0217751x20400217 ◽

2020 ◽

Vol 35 (02n03) ◽

pp. 2040021

Author(s):

Alexander A. Chernitskii

Keyword(s):

Field Theory ◽

Long Range ◽

Nonlinear Electrodynamics ◽

Nonlinear Field ◽

Unified Field Theory ◽

Film Model ◽

Fundamental Interactions ◽

Unified Field ◽

World Volume ◽

Quantum Behavior

The concept of unified field theory is discussed. Two nonlinear field models with world volume type action are considered, namely extremal space-time film model and Born–Infeld nonlinear electrodynamics. The natural appearance of two long-range fundamental interactions, electromagnetism and gravitation, in these field models is discussed. The quantum behavior of the interacting solitons-particles is considered. The concept of quasi-bounding quantization in nonlinear field models is introduced.

Download Full-text

Seti Space Missions

International Astronomical Union Colloquium ◽

10.1017/s0252921100015372 ◽

1997 ◽

Vol 161 ◽

pp. 761-776 ◽

Cited By ~ 1

Author(s):

Claudio Maccone

Keyword(s):

Electromagnetic Waves ◽

Space Missions ◽

Gravitational Lens ◽

The Sun ◽

Space Antenna ◽

Focal Distance ◽

Large Space ◽

The Earth ◽

Space Antennas ◽

New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Download Full-text