Related papers: Towards a realistic axion star
We present a brief review of general results about non-rotating neutron stars in simple R-square gravity and its extension with a scalar axion field. Modified Einstein equations are presented for metrics in isotropical coordinates. The…
Understanding axion cosmology has important experimental consequences since it constrains the range of allowed values for the axion mass. In the standard thermal scenario, which assumes Peccei-Quinn symmetry restoration after inflation, an…
In static and spherically symmetric spacetime, we solve the Einstein Maxwell equations. The effective gravitational potential and the electric field for charged anisotropic fluid are defined in terms of two free parameters. For such…
We present solutions to the Einstein-Klein Gordon system representing boson stars in the slow rotation approximation. By considering slow rotation we are able to reduce the number of equations yielding a system of ordinary differential…
The thermal evolution of a neutron star is studied by including the energy loss due to axion emission. Two axion models and three types of neutron-star matter equation of state are used with the effects of nucleon superfluidity properly…
We review particle-like configurations of complex scalar field, localized by gravity, so-called boson stars. In the simplest case, these solutions posses spherical symmetry, they may arise in the massive Einstein-Klein-Gordon theory with…
We provide a compact review on recent developments on axion $F(R)$ gravity. The axion field is a string theory originating theoretical particle that is a perfect candidate for low-mass particle dark matter. In this review we present how a…
When axion stars fly through an astrophysical magnetic background, the axion-to-photon conversion may generate a large electromagnetic radiation power. After including the interference effects of the spacially-extended axion-star source and…
If the dark matter is composed of axions, then axion stars are expected to be abundant in the Universe. We demonstrate in fully non-linear (3+1) numerical relativity the instability of compact axion stars due to the electromagnetic…
Axions are hypothetical pseudoscalar particles that have been regarded as promising dark matter (DM) candidates. On the other hand, extended compact objects such as axion stars, which are supported by gravity and axion self interactions,…
We study charged and rotating boson stars in 5-dimensional Einstein-Maxwell(-Chern-Simons) theory assuming the two angular momenta associated to the two orthogonal planes of rotation to be equal. Next to the angular momenta, the boson stars…
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…
Recent work has shown that axions can be efficiently produced via non-stationary pair plasma discharges in the polar cap region of pulsars. Here, we point out that for axion masses $10^{-9} \, {\rm eV} \lesssim m_a \lesssim 10^{-4} \, \rm…
We demonstrate that the observed cosmological excess of matter over antimatter may originate from a heavy QCD axion that solves the strong CP problem but has a mass much larger than that given by the Standard Model QCD strong dynamics. We…
We investigate a novel gravitational configuration formed by a massless real phantom field and an axion scalar field, minimally coupled to gravity. This system describes an Ellis-type wormhole situated at the center of an axion star. By…
We showed that compact bosonic objects can be formed through a process we called gravitational cooling. A central issue in the subject of boson star is whether a classical field configuration, {\it e.g.,} one described by the Klein-Gordon…
We present new spherically symmetric solutions of the Einstein-Klein-Gordon equations in a quasi-stationary approximation that describe self-gravitating scalar field configurations around a black hole, including angular momentum number…
We investigate the possible gravitational redshift values for boson stars with a self-interaction, studying a wide range of possible masses. We find a limiting value of $z_{lim} \simeq 0.687$ for stable boson star configurations. We compare…
Orbiting $\gamma$-detectors combined with the magnetic field of the Earth or the Sun can work parasitically as cosmic axion telescopes. The relatively short field lengths allow the axion-to-photon conversion to be coherent for $m_{axion}…
We present a self-consistent, relativistic model of rapidly rotating neutron stars describing their exterior gravitational field. This is achieved by matching the new solution of Einstein's field equations found by Manko et al. (2000) and…