Observational imprints of gravastars from accretion disks and hot-spots
arXiv:2401.07766 · doi:10.1103/PhysRevD.109.084002
Abstract
In this work, we analyze the observational properties of thin-shell gravastars under two astrophysical frameworks, namely surrounded by optically-thin accretion disks and orbited by hot-spots. We consider the thin-shell gravastar model with two free parameters, the gravastar radius and ratio of mass allocated at the thin-shell, and produce the corresponding observables via the use of numerical backwards ray-tracing codes. Regarding the observations of accretion disks, our results indicate that, due to the absence of a strong gravitational redshift effect, smooth gravastar configurations cannot reproduce shadow observations when internal emission is assumed. We thus expect such models to be excluded as candidates for supermassive objects in galactic cores. Nevertheless, thin-shell gravastars with a large portion of their total mass allocated at the surface can produce such an effect and are thus adequate candidates for black-hole mimickers. In the context of hot-spot orbits, the astrometrical observational properties of ultra-compact gravastars resemble closely those of other ultra-compact objects e.g. fluid stars and bosonic stars. However, for low-compacticity configurations, the time-integrated fluxes feature additional contributions in the form of a high-intensity plunge through image. These qualitative differences in the observational properties of gravastars in comparison with black-hole spacetimes could potentially be discriminated by the next generation of interferometric experiments in gravitational physics.
20 pages, 16 Figures. v2: published version
References in corpus (13)
- First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
- The Confrontation between General Relativity and Experiment
- First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
- Echoes of ECOs: gravitational-wave signatures of exotic compact objects and of quantum corrections at the horizon scale
- Tests for the existence of horizons through gravitational wave echoes
- How to tell a gravastar from a black hole
- The imitation game: Proca stars that can mimic the Schwarzschild shadow
- Can accretion disk properties distinguish gravastars from black holes?
- Images and photon ring signatures of thick disks around black holes
- Observational properties of relativistic fluid spheres with thin accretion disks
- Superradiance in stars
- Existence and stability of relativistic fluid spheres supported by thin shells
- 3+1 geodesic equation and images in numerical spacetimes