On the Size of Rotating Black Holes

Abstract

Recently a sequence of inequalities relating the black hole horizon, photon sphere, shadow were proposed for spherically symmetric and static black holes, providing the upper bound for given mass. In this paper, we extend the discussion to include rotating black holes. When viewed from the north pole direction, the shadow remains a round disk, but the image is skewed when viewed from the equatorial plane. After properly implementing the ``size'' parameters for the rotating black holes, we verify that the sequence of inequalities remain valid for a variety of solutions, including Kerr, Kerr-Newman, Kerr-Sen and Kerr-Cveti\v c-Youm black holes. The upshot is that rotation makes both the actual and apparent sizes of a black hole smaller.

arXiv commentLatex, 33 pages

References in corpus (38)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• The geometry of photon surfaces
• Shadows of Kerr black holes with scalar hair
• Testing the rotational nature of the supermassive object M87* from the circularity and size of its first image
• Rotating Charged Black Hole Solution in Heterotic String Theory
• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• Relativistic images of Schwarzschild black hole lensing
• Photon Regions and Shadows of Kerr-Newman-NUT Black Holes with a Cosmological Constant
• Shadow of rotating regular black holes
• A new method for shadow calculations: application to parameterised axisymmetric black holes
• Apparent shape of super-spinning black holes
• Four Dimensional String/String/String Triality
• Shadow of five-dimensional rotating Myers-Perry black hole
• Black hole shadow in an asymptotically-flat, stationary, and axisymmetric spacetime: The Kerr-Newman and rotating regular black holes
• Entropy of Non-Extreme Charged Rotating Black Holes in String Theory
• Black hole shadow in an expanding universe with a cosmological constant
• Black hole shadow in a general rotating spacetime obtained through Newman-Janis algorithm
• Charged Rotating Black Holes in Four-Dimensional Gauged and Ungauged Supergravities
• Hidden symmetries, null geodesics, and photon capture in the Sen black hole
• Incidences between points and lines on a two-dimensional variety
• Modified Gravity Black Holes and their Observable Shadows
• Curvature radius and Kerr black hole shadow
• Photon Spheres and Sonic Horizons in Black Holes from Supergravity and Other Theories
• Shadows, Signals, and Stability in Einsteinian Cubic Gravity
• Present status of the Penrose inequality
• Shadow cast by rotating braneworld black holes with a cosmological constant
• Upper bound on the radii of black-hole photonspheres
• Einstein-scalar-Gauss-Bonnet black holes: Analytical approximation for the metric and applications to calculations of shadows
• Shadows of Kerr-like black holes in a modified gravity theory
• Shadows of Bonnor black dihole by chaotic lensing
• Intrinsic curvature and topology of shadows in Kerr spacetime
• Shadow of a Charged Rotating Non-Commutative Black Hole
• The fastest way to circle a black hole
• On the Size of a Black Hole: The Schwarzschild is the Biggest
• Shadow of charged black holes in Gauss-Bonnet gravity
• Quasi-local photon surfaces in general spherically symmetric spacetimes
• Can shadows reflect phase structures of black holes?
• Quasi-topological Electromagnetism: Dark Energy, Dyonic Black Holes, Stable Photon Spheres and Hidden Electromagnetic Duality

Cited by in corpus (35)

• Shadow of a Spinning Black Hole in an Expanding Universe
• Influence of Quantum Correction on the Black Hole Shadows, Photon Rings and Lensing Rings
• QED Effect on Black Hole Shadow
• Shadow analysis for rotating black holes in the presence of plasma for an expanding universe
• Imprints of Dark Matter on Black Hole Shadows using Spherical Accretions
• Modelling the Sgr A* Black Hole Immersed in a Dark Matter Spike
• Shadow and stability of quantum-corrected black holes
• Einstein-Æther Gravity in the light of Event Horizon Telescope Observations of M87*
• Shadow, quasinormal modes and quasiperiodic oscillations of rotating Kaluza-Klein black holes
• Constraints on Barrow entropy from M87* and S2 star observations
• Dark matter spike around Bumblebee black holes
• Testing the nature of Gauss-Bonnet gravity by four-dimensional rotating black hole shadow
• Study of circular geodesics and shadow of rotating charged black hole surrounded by perfect fluid dark matter immersed in plasma
• Silhouettes of invisible black holes
• Black holes in dRGT massive gravity with the signature of EHT observations of M87*
• Shadows, rings and optical appearance of a magnetically charged regular black hole illuminated by various accretion disks
• NUT charges and black hole shadows
• Testing Born-Infeld $f(T)$ teleparallel gravity through Sgr A${}^{\star }$ observations
• Killing tensors and photon surfaces in foliated spacetimes
• Kerr-Newman Black Holes in Weyl-Cartan Theory: Shadows and EHT constraints
• Thin accretion disk and shadow of Kerr-Sen black hole in Einstein-Maxwell-dilaton-axion gravity
• Kerr spacetime geometric optics for vortex beams
• GUP-corrected black holes: Thermodynamic properties, evaporation time and shadow constraint from EHT Observations of M87* and Sgr A*
• Slice-reducible conformal Killing tensors, photon surfaces and shadows
• Connections between the shadow radius and the quasinormal modes of Kerr-Sen black hole
• Equatorial and polar quasinormal modes and quasiperiodic oscillations of quantum deformed Kerr black hole
• Shadow of Kottler black hole in the presence of plasma for a co-moving observer
• Modified Kerr black holes surrounded by dark matter spike
• Can we know about black hole thermodynamics through shadows?
• Non-Equatorial Deflection of Light due to Kerr-Newman Black Hole: A Material Medium Approach
• Constraining rotating black hole via curvature radius with observations of M87*
• Analyzing the Influence of Geometrical Deformation on Photon Sphere and Shadow Radius: A New Analytical Approach -Stationary, and Axisymmetric Spacetime
• Higher-dimensional electric-magnetic photon sphere uniqueness
• Visible shapes of black holes M87* and SgrA*
• Uniqueness of electric-magnetic spacetimes with massive particle