Three observables on a standardized segment of the Kerr critical curve uniquely fix spin a/M, inclination i, and segment location r_nl within the considered domain.
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First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
Canonical reference. 88% of citing Pith papers cite this work as background.
abstract
We present the first Event Horizon Telescope (EHT) images of M87, using observations from April 2017 at 1.3 mm wavelength. These images show a prominent ring with a diameter of ~40 micro-as, consistent with the size and shape of the lensed photon orbit encircling the "shadow" of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. To assess the reliability of these results, we implemented a two-stage imaging procedure. In the first stage, four teams, each blind to the others' work, produced images of M87 using both an established method (CLEAN) and a newer technique (regularized maximum likelihood). This stage allowed us to avoid shared human bias and to assess common features among independent reconstructions. In the second stage, we reconstructed synthetic data from a large survey of imaging parameters and then compared the results with the corresponding ground truth images. This stage allowed us to select parameters objectively to use when reconstructing images of M87. Across all tests in both stages, the ring diameter and asymmetry remained stable, insensitive to the choice of imaging technique. We describe the EHT imaging procedures, the primary image features in M87, and the dependence of these features on imaging assumptions.
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background 8representative citing papers
Scalarized Kerr-Newman black holes develop an inner photon shell that produces an additional critical curve and distinct crescent-like higher-order images unlike those in Kerr spacetime.
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
Presents an observability framework for solar gravitational lens astronomy and reports SSIM values of 0.993, 0.918, 0.973, and 0.923 for scalar reconstructions of four analytic scenes under stated assumptions.
Spinning test particles around rotating hairy black holes show finite-time instability in localized regions of the (spin, hair-parameter) plane that reorganize the strong-field phase space compared to Kerr.
Superradiant axion-like-particle clouds around rotating black holes can generate multimode squeezed graviton states with 10^6-10^7 correlated quanta showing polarization correlations and quantum-noise signatures potentially detectable by future interferometers.
Scalarized black holes in EMS theory lack smooth Cauchy horizons and form Kasner singularities, with a scaling relation between Kasner parameter and charge-to-mass ratio near criticality.
Three distinct non-minimal curvature-EM couplings produce different enlargements or reductions of black hole shadows and alter photon ring separations in characteristic ways.
Superradiant amplification of charged scalar fields around rotating charged de Sitter black holes is suppressed in conformal Weyl gravity relative to general relativity, with strong exponential suppression for massive fields in the cosmological region.
Boson stars in teleparallel gravity with nonminimal coupling show negative energy density and energy-condition violation in excited states, with EMRI waveforms potentially detectable by LISA.
Analysis of how string cloud parameter a and dark matter parameter α alter MBO, ISCO, periodic orbits indexed by q, and the gravitational waveforms generated by those orbits in a modified Schwarzschild spacetime.
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
Nonlocal gravity shrinks the ISCO radius, boosts QPO frequencies, and constrains α/M ≤ 0.452 with M ≲ 43.6 M_⊙ for observed high-frequency QPOs under resonance models.
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
Rotating Ayón-Beato-García black holes produce smaller and sometimes D-shaped shadows whose size constrains the charge parameter ζ to the range 0.132811M–0.213607M when matched to EHT observations of M87* and Sgr A*.
GRRT simulations show that raising the dilaton parameter shrinks the bright ring while increasing its width and brightness, disk thickness reduces diameter and width with weaker brightness impact, and both affect allowed ranges versus EHT Sgr A* data and the polarization coefficient beta2.
An exact AdS extension of the PINLED black hole is derived from the Einstein-Hilbert action plus nonlinear EM sector, preserving the original parametric form while adding the standard AdS lapse term, followed by full thermodynamic and geodesic analysis.
CUDA-based ray tracing shows black hole shadows and emission rates vary with global monopole, charge, and rotation parameters but are insensitive to the Euler-Heisenberg nonlinearity, yielding observational bounds on those three quantities.
Energy extraction via Comisso-Asenjo magnetic reconnection from rotating dyonic black holes in N=2 U(1)^2 gauged supergravity is possible but tightly limited by gauge coupling g and dyonic charges, peaking at intermediate spins rather than near-extremal.
A thermodynamic treatment of charged black holes is proposed to connect swampland conjectures to the dark dimension and dark matter using dynamical cosmological constant and quasi-static scalar fields.
citing papers explorer
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Determining Kerr black hole spin and inclination from a segment of the critical curve in black hole images
Three observables on a standardized segment of the Kerr critical curve uniquely fix spin a/M, inclination i, and segment location r_nl within the considered domain.
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Optical Appearance of Scalarized Kerr-Newman Black Holes with Multiple Light Rings
Scalarized Kerr-Newman black holes develop an inner photon shell that produces an additional critical curve and distinct crescent-like higher-order images unlike those in Kerr spacetime.
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Identifying Observational Signatures of Flux Eruption Events in Supermassive Black Hole Accretion Flows with Machine Learning
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
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Ultra-High-Resolution Astronomy with the Solar Gravitational Lens
Presents an observability framework for solar gravitational lens astronomy and reports SSIM values of 0.993, 0.918, 0.973, and 0.923 for scalar reconstructions of four analytic scenes under stated assumptions.
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Spin-Hair Induced Chaos of Spinning Test Particles in Rotating Hairy Black Holes
Spinning test particles around rotating hairy black holes show finite-time instability in localized regions of the (spin, hair-parameter) plane that reorganize the strong-field phase space compared to Kerr.
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How Much Can Gravitons Be Squeezed?
Superradiant axion-like-particle clouds around rotating black holes can generate multimode squeezed graviton states with 10^6-10^7 correlated quanta showing polarization correlations and quantum-noise signatures potentially detectable by future interferometers.
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Critical phenomenon inside asymptotically flat black holes with spontaneous scalarization
Scalarized black holes in EMS theory lack smooth Cauchy horizons and form Kasner singularities, with a scaling relation between Kasner parameter and charge-to-mass ratio near criticality.
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Photon rings and shadows of black holes with non-minimal couplings between curvature and electromagnetic field
Three distinct non-minimal curvature-EM couplings produce different enlargements or reductions of black hole shadows and alter photon ring separations in characteristic ways.
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Superradiant Suppression of Non-minimally Coupled Scalar fields for a Rotating Charged dS Black Hole in Conformal Weyl Gravity
Superradiant amplification of charged scalar fields around rotating charged de Sitter black holes is suppressed in conformal Weyl gravity relative to general relativity, with strong exponential suppression for massive fields in the cosmological region.
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Boson Stars in Teleparallel Gravity with a Nonminimally Coupled Field: The Violation of Energy Conditions and Gravitational Waveforms from EMRIs
Boson stars in teleparallel gravity with nonminimal coupling show negative energy density and energy-condition violation in excited states, with EMRI waveforms potentially detectable by LISA.
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Periodic orbits and gravitational waveforms around a Schwarzschild black hole with a cloud of strings embedded in perfect fluid dark matter
Analysis of how string cloud parameter a and dark matter parameter α alter MBO, ISCO, periodic orbits indexed by q, and the gravitational waveforms generated by those orbits in a modified Schwarzschild spacetime.
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Dimming of Photon Ring due to Photon-Axion Conversion around Kerr Black Holes
Photon-axion conversion near Kerr black holes produces dimming of photon spectral luminosity that increases with black hole spin, magnetic field strength, and photon-axion coupling, most efficiently at high frequencies.
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The properties and predictions of quasi-periodic oscillations around a black hole in nonlocal gravity
Nonlocal gravity shrinks the ISCO radius, boosts QPO frequencies, and constrains α/M ≤ 0.452 with M ≲ 43.6 M_⊙ for observed high-frequency QPOs under resonance models.
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GRMHD and GRRT Simulations of Black Hole Accretion: Flares, Precession, and Complex Spacetimes
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
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Observational Signatures of Rotating Ay\'{o}n-Beato-Garc\'{i}a Black Holes: Shadows, Accretion Disks and Images
Rotating Ayón-Beato-García black holes produce smaller and sometimes D-shaped shadows whose size constrains the charge parameter ζ to the range 0.132811M–0.213607M when matched to EHT observations of M87* and Sgr A*.
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Bright ring features and polarization structures in Kerr-Sen black hole images illuminated by radiatively inefficient accretion flows
GRRT simulations show that raising the dilaton parameter shrinks the bright ring while increasing its width and brightness, disk thickness reduces diameter and width with weaker brightness impact, and both affect allowed ranges versus EHT Sgr A* data and the polarization coefficient beta2.
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Thermodynamics and orbital structure of anti-de Sitter black holes in Palatini-inspired nonlinear electrodynamics
An exact AdS extension of the PINLED black hole is derived from the Einstein-Hilbert action plus nonlinear EM sector, preserving the original parametric form while adding the standard AdS lapse term, followed by full thermodynamic and geodesic analysis.
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On Computational CUDA Studies of Black Hole Shadows
CUDA-based ray tracing shows black hole shadows and emission rates vary with global monopole, charge, and rotation parameters but are insensitive to the Euler-Heisenberg nonlinearity, yielding observational bounds on those three quantities.
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Energy Extraction via Magnetic Reconnection from a Rotating Dyonic Black Hole in $N = 2, \ U(1)^2$ Gauged Supergravity
Energy extraction via Comisso-Asenjo magnetic reconnection from rotating dyonic black holes in N=2 U(1)^2 gauged supergravity is possible but tightly limited by gauge coupling g and dyonic charges, peaking at intermediate spins rather than near-extremal.
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On Thermodynamics of Charged Black Holes, Swampland, and Dark Matter
A thermodynamic treatment of charged black holes is proposed to connect swampland conjectures to the dark dimension and dark matter using dynamical cosmological constant and quasi-static scalar fields.
- Photon Propagation and Black Hole Imaging in Kruglov Nonlinear Electrodynamics