Observers in Kerr spacetimes: the ergoregion on the equatorial plane

Abstract

We perform a detailed analysis of the properties of stationary observers located on the equatorial plane of the ergosphere in a Kerr spacetime, including light-surfaces. This study highlights crucial differences between black hole and the super-spinner sources. In the case of Kerr naked singularities, the results allow us to distinguish between "weak" and "strong" singularities, corresponding to spin values close to or distant from the limiting case of extreme black holes, respectively. We derive important limiting angular frequencies for naked singularities. We especially study very weak singularities as resulting from the spin variation of black holes. We also explore the main properties of zero angular momentum observers for different classes of black hole and naked singularity spacetimes.

20 pages, 13 multi-panels figures, 2 tables

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Cited by in corpus (14)

• Parameter estimation of hairy Kerr black holes from its shadow and constraints from M87*
• General relativistic rotational energy extraction from black holes-accretion disk systems
• Disclosing connections between black holes and naked singularities: Horizon remnants, Killing throats and bottlenecks
• Proto-jets configurations in RADs orbiting a Kerr SMBH: symmetries and limiting surfaces
• Slice-reducible conformal Killing tensors, photon surfaces and shadows
• Constraining LQG Graph with Light Surfaces: Properties of BH Thermodynamics for Mini-Super-Space, Semi-Classical Polymeric BH
• Shadows and parameter estimation of rotating quantum corrected black holes and constraints from EHT observation of M87* and Sgr A*
• The equatorial motion of the charged test particles in Kerr-Newman-Taub-NUT spacetime
• Dragged surfaces. On the accretion tori in the ergoregion
• Jet collision with accreting tori around SMBHs. GRHD and light surfaces constraints in aggregates of misaligned tori
• Repulsive gravity effects in horizon formation. Horizon remnants in naked singularities
• Extracting information on black hole horizons
• Evolution of Braneworld Kerr-Newman Naked Singularities
• Lense-Thirring effect on accretion flow from counter-rotating tori