Ergoregion instability of exotic compact objects: Electromagnetic and gravitational perturbations and the role of absorption

@article{Maggio2019ErgoregionIO,
  title={Ergoregion instability of exotic compact objects: Electromagnetic and gravitational perturbations and the role of absorption},
  author={Elisa Maggio and Vitor Cardoso and Sam R. Dolan and Paolo Pani},
  journal={Physical Review D},
  year={2019}
}
Spinning horizonless compact objects may be unstable against an ``ergoregion instability.'' We investigate this mechanism for electromagnetic perturbations of ultracompact Kerr-like objects with a reflecting surface, extending previous (numerical and analytical) work limited to the scalar case. We derive an analytical result for the frequency and the instability timescale of unstable modes which is valid at small frequencies. We argue that our analysis can be directly extended to gravitational… 

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References

SHOWING 1-10 OF 137 REFERENCES

Exotic Compact Objects and How to Quench their Ergoregion Instability

Gravitational-wave astronomy can give us access to the structure of black holes, potentially probing microscopic or even Planckian corrections at the horizon scale, as those predicted by some

Ergoregion instability of ultracompact astrophysical objects

Most of the properties of black holes can be mimicked by horizonless compact objects such as gravastars and boson stars. We show that these ultracompact objects develop a strong ergoregion

On the ergoregion instability

  • N. CominsB. Schutz
  • Physics
    Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
  • 1978
Rotating, ultra-compact stars in general relativity can have an ergo-region, in which all trajectories are dragged in the direction of the star’s rotation. The existence of the ergoregion leads to a

Light rings as observational evidence for event horizons: Long-lived modes, ergoregions and nonlinear instabilities of ultracompact objects

Ultracompact objects are self-gravitating systems with a light ring. It was recently suggested that fluctuations in the background of these objects are extremely long-lived and might turn unstable at

The stochastic gravitational-wave background in the absence of horizons

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

Gravitational instabilities of superspinars

Superspinars are ultracompact objects whose mass M and angular momentum J violate the Kerr bound (cJ/GM^2>1). Recent studies analyzed the observable consequences of gravitational lensing and

Gravitational-wave signatures of exotic compact objects and of quantum corrections at the horizon scale

Gravitational waves from binary coalescences provide one of the cleanest signatures of the nature of compact objects. It has been recently argued that the postmerger ringdown waveform of exotic

Gravitational wave signatures of the absence of an event horizon: Nonradial oscillations of a thin-shell gravastar

Gravitational waves from compact objects provide information about their structure, probing deep into strong-gravity regions. Here we illustrate how the presence or absence of an event horizon can

Testing strong-field gravity with tidal Love numbers

The tidal Love numbers (TLNs) encode the deformability of a self-gravitating object immersed in a tidal environment and depend significantly both on the object's internal structure and on the
...