Related papers: Ultracompact vector stars
Neutron stars and black holes are the astrophysical systems with the strongest gravitational fields in the universe. In this article, I review the prospect of probing with observations of such compact objects some of the most intriguing…
Black holes are thought to describe the geometry of massive, dark compact objects in the universe. To further support and quantify this long-held belief requires knowledge of possible, if exotic alternatives. Here, we wish to understand how…
Vector unparticle couplings to standard model fields produce repulsive corrections to gravity. From a general relativistic perspective, this leads to an effective Reissner-Nordstr\"om-like metric whose "charge" is a function of the…
We classify orbits of stars that are bound to central black holes in galactic nuclei. The stars move under the combined gravitational influences of the black hole and the central star cluster. Within the sphere of influence of the black…
Compact relativistic stars allow us to study the nature of matter under extreme conditions, probing regions of parameter space that are otherwise inaccessible. Nuclear theory in this regime is not well constrained: one key issue is whether…
The primary objective of this paper is to investigate the notions of geometric and sequential convexity within a graph-theoretic framework, with the aim of examining various structural properties and exploring the connection between these…
We consider compact boson stars that arise for a V-shaped scalar field potential. They represent a one parameter family of solutions of the scaled Einstein-signum-Gordon equations. We analyze the physical properties of these solutions and…
In the present investigation compact stellar models are dealt with in the framework of the modified gravity theory, specifically of $f(\mathbb{T},\mathcal{T})$ type. We have considered that the compact objects are following a spherically…
Ultralight bosons, which are predicted in a variety of beyond-Standard-Model scenarios as dark-matter candidates, can trigger the superradiant instability around spinning black holes. This instability gives rise to oscillating boson…
Taking advantage of a previously developed method, which allows to map solutions of General Relativity into a broad family of theories of gravity based on the Ricci tensor (Ricci-based gravities), we find new exact analytical scalar field…
We consider neutron star configurations in the scalar-tensor theory of gravity with the coupling between the kinetic term of a scalar field and the Einstein tensor (such the model is a subclass of Horndeski gravity). Neutron stars in this…
We construct the exact stellar configurations that contain an ordinary perfect-fluid matter that interacts minimally with a condensate of gravitons with distinct pressure conditions on the surface. We propose vanishing transverse pressure…
Recently, theoretical studies on the bumblebee gravity model, a nonminimally-coupled vector-tensor theory that violates the Lorentz symmetry, have flourished, with a simultaneous increase in the utilization of observations to impose…
We consider a general class of vector-tensor theories of gravity and show that solutions with accelerated expansion and a future type III singularity are a common feature in these models. We also show that there are only six vector-tensor…
Compact object perturbations, at linear order, often lead in solving one or more coupled wave equations. The study of these equations was typically done by numerical or semi-analytical methods. The WKB method and the associated…
This paper delves into the impact of extended symmetric teleparallel theory on anisotropic compact stellar structures. The explicit field equations were formulated by considering a minimum model of this extended gravity. Basically, the…
We test the hypothesis that the starless cores may be gravitationally bound clouds supported largely by thermal pressure by comparing observed molecular line spectra to theoretical spectra produced by a simulation that includes…
It is by now well established that non-relativistic matter in the Universe is dominated by dark matter, the origin and nature of which still remains a mystery. Although the collisionless dark matter paradigm works very well at large…
In this paper we study the phenomenology of stars and galaxies in massive bigravity. We give parameter conditions for the existence of viable star solutions when the radius of the star is much smaller than the Compton wavelength of the…
In this work we consider the observational properties of compact boson stars with self-interactions orbited by isotropically emitting (hot-spot) sources and optically thin accretion disks. We consider two families of boson stars supported…