相关论文: On the ergoregion instability in rotating gravasta…

Gravitational-wave astronomy has the potential to explore one of the deepest and most puzzling aspects of Einstein's theory: the existence of black holes. A plethora of ultracompact, horizonless objects have been proposed to arise in models…

The near-horizon geometries of the spinning D3-, M2- and M5-branes are examined by the probes immersed in a co-rotating frame. It is found that the geometries become unstable at critical values of the spin angular velocity by emitting the…

As a most promising candidate for quantum theory of the gravity, the superstring theory has attracted many researchers including cosmologists. It is expected that the cosmological initial singularity is avoided within the context of the…

It has been argued that ultracompact objects, which possess light rings but no horizons, may be unstable against gravitational perturbations. To test this conjecture, we revisit the quasi-black hole solutions, a family of horizonless…

We consider the combined role of the thermal ionization, magneto-rotational and gravitational instabilities in thin accretion disks around supermassive black holes. We find that in the portions of the disk unstable to the ionization…

The dynamics of a rigid, rotating, precessing, massive ring orbiting a point mass within the perimeter of the ring are considered. It is demonstrated that orbits dynamically stable against perturbations in three dimensions exist for a range…

With n-body simulations and analytic approximations we study the dynamics and stability of low eccentricity misaligned test particles around binary systems with varying mass fraction and eccentricity. General relativity (GR) plays a primary…

One of the main challenges in astronomy is the direct observation of black holes. However, differentiating them from black holes through photon observations can be difficult if Ultra-Compact Objects with unstable circular photon orbits…

We construct the solutions of slowly rotating gravastars with a thin shell. In the zero-rotation limit, we consider the gravastar composed of a de Sitter core, a thin shell, and Schwarzschild exterior spacetime. The rotational effects are…

Accretion disks around compact objects are expected to enter an unstable phase at high luminosity. One instability may occur when the radiation pressure generated by accretion modifies the disk viscosity, resulting in the cyclic depletion…

This work proposes a stellar model under Gauss-Bonnet $f(\mathcal{G}, T)$ gravity with the conjecture theorised by Mazur and Mottola, well known as the gravitational vacuum stars (gravastars). By taking into account the $f(\mathcal{G},T)$…

Gravastars are configurations of compact singularity-free gravitational objects which are interesting alternatives to classical solutions in the strong gravitational field regime. Although there are no static star-like solutions of the…

Dynamical instability is shown to occur in differentially rotating polytropes with N = 3.33 and $T/|W| \gtrsim 0.14$. This instability has a strong m=1 mode, although the m=2, 3, and 4 modes also appear. Such instability may allow a…

Black holes in $f(R)$-gravity are known to be unstable, especially the rotating ones. In particular, an instability develops that looks like the classical black hole bomb mechanism: the linearized modified Einstein equations are…

The interest in the implications that astrophysical observations have for the understanding of the structure of black holes has grown since the first detection of gravitational waves. Many arguments that are put forward in order to…

We study the superradiant instability of massive vector fields, i.e. Proca fields, around spinning black holes in the test field limit. This is motivated by the possibility that observations of astrophysical black holes can probe the…

Gravitational instability is one of considerable mechanisms to explain the formation of giant planets. We study the gravitational stability for the protoplanetary disks around a protostar. The temperature and Toomre's Q-value are calculated…

Various higher-dimensional black holes have been shown to be unstable by studying linearized gravitational perturbations. A simpler method for demonstrating instability is to find initial data that describes a small perturbation of the…

Exotic compact objects (ECOs) have recently become an exciting research subject, since they are speculated to have a special response to the incident gravitational waves (GWs) that leads to GW echoes. We show that energy carried by GWs can…

The gravastar model, which postulates a strongly correlated thin shell of anisotropic matter surrounding a region of anti-de Sitter space, has been proposed as an alternative to black holes. We discuss constraints that present-day…