Multi-frequency VLBI observations detect a two-sided jet with steep synchrotron spectrum from the nearly dormant SMBH in M60, with frequency-dependent core shift locating the engine ~10 Schwarzschild radii upstream of the 8.37 GHz core.
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First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
Canonical reference. 89% of citing Pith papers cite this work as background.
abstract
When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42+/-3 micro-as, which is circular and encompasses a central depression in brightness with a flux ratio ~10:1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5+/-0.7) x 10^9 Msun. Our radio-wave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible.
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- abstract When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter o
- background Bisnovatyi-Kogan, Phys. Rev. D 97, 104062 (2018) , arXiv:1804.04898 [gr-qc] . [50] G. S. Bisnovatyi-Kogan and O. Y. Tsupko, Universe 3, 57 (2017) , arXiv:1905.06615 [gr-qc] . [51] G. S. Bisnovatyi-Kogan and O. Y. Tsupko, Phys. Rev. D 98, 084020 (2018) , arXiv:1805.03311 [gr-qc] . [52] O. Yu. Tsupko, Phys. Rev. D95, 104058 (2017) , arXiv:1702.04005 [gr-qc] . [53] O. Y. Tsupko, Int. J. Mod. Phys. D 27, 1844020 (2018) . [54] O. Y. Tsupko, Z. Fan, and G. S. Bisnovatyi- Kogan, Class. Quant. Grav. 37,
- background [LIGO Scientific and Virgo], "Ob- servation of Gravitational Waves from a Binary Black Hole Merger," Phys. Rev. Lett.116, no.6, 061102 (2016) [arXiv:1602.03837 [gr-qc]]. [84] K. Akiyamaet al.[Event Horizon Telescope], "First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole," Astrophys. J. Lett.875, L1 (2019) [arXiv:1906.11238 [astro-ph.GA]]. [85] A. Maselli, N. Franchini, L. Gualtieri, T. P. Sotiriou, S. Barsanti and P. Pani, "Detecting fundamental fields with LI
- background Therefore, we focus on the BH shadow as a viable probe of the strong-gravity regime. The shadow corre- sponds to the set of directions on the observer's sky from which photons cannot escape to infinity and are instead captured by the central object; its boundary is deter- mined by unstable photon orbits and is closely related to the photon ring observed in horizon-scale imaging [4, 90]. In the generic spacetime (5), the BH shadow is a circle that does not depend on the observer's inclination ang
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representative citing papers
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.
In the rotating García-Díaz NLED black hole the Fresnel quartic factorizes into two optical metrics whose critical families project to distinct contours Γ+ and Γ- whose angular separation is generated by the constitutive response and redistributed by spin.
A gravitational-wave method infers the Kerr-equivalent horizon area from direct waves in the near-merger signal of GW250114, yielding consistency with the Kerr remnant and a new test of Hawking's area law.
A covariant framework is developed for photon surfaces in dynamical spherical spacetimes, recovering static limits and applied to collapse and accretion/evaporation models.
In massive scalar-tensor gravity, rotating neutron stars that collapse emit nearly the same tensor gravitational waves as in general relativity, but lose about 10^-3 solar masses of energy in scalar radiation - far more than the quadrupole channel.
Kerr black holes in an EsGB model without linear instability undergo nonlinear scalarization above spin 0.5, existing in a finite low-mass high-spin wedge rather than a narrow band.
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
Surface-gravity waves in shallow water can be configured with central and graded drainage to analogize regular black holes and mimickers, enabling lab study of their instabilities.
The authors derive relativistic drift-kinetic moment equations and a new analytic Landau fluid closure that incorporates anisotropic heat conduction and Landau damping without assuming collisional thermalization.
Derives a factorized leading term for the strong deflection angle near degenerate photon spheres using local expansion of the effective potential and Weyl tensor measures.
An exact Debye-series decomposition of the scattering matrix for waves on compact stars reveals distinct Regge-Debye pole families that dominate amplitudes differently in neutron-star-like and ultracompact regimes.
Stupendously large black holes cast shadows on the CMB that rule out masses above 10^17 solar masses within the last scattering surface and limit their density parameter to below 10^-5 for masses 10^15 to 10^18 solar masses.
Rotating black holes with primary scalar hair in beyond Horndeski gravity produce shadows whose diameter increases for negative Q and whose distortion increases for positive Q, with EHT bounds on M87* restricting but not ruling out the (a, Q) parameter space.
ABG-dS black holes show charged superradiant instability exclusively for the spherically symmetric ℓ=0 mode, with growth rates that peak at intermediate Λ and q and rise with Q, differing from RN-dS due to nonlinear electrodynamics.
Self-force theory is extended to compute merger and ringdown waveforms in beyond-GR black hole binaries under the extreme mass-ratio approximation, with first calculations of self-force corrections to the merger waveform.
In dRGT massive gravity, static spherically symmetric black holes exhibit zero, one, or two photon spheres whose topological charges and stability patterns differ from Einstein gravity and from horizonless compact objects.
Regular Vaidya solutions exist in effective gravitational theories that dynamically describe radiation-driven formation of regular black holes or mimickers without curvature singularities.
Stable neutron-star configurations denser than black holes exist in quasi-topological gravity and may produce detectable gravitational-wave echoes.
VAPOLA releases multi-epoch multi-band ALMA full-Stokes products and polarimetric fits for AGN and Sgr A* via an automated pipeline and web portal.
Steady GRMHD jets exhibit a universal near-horizon polarization pattern set only by black hole spin, with large-radius polarization angle following a collimation-determined power law and intermediate scales modified by plasma loading.
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.
VLBI observations of TXS 0506+056 show a spine-sheath jet with aligned inner and perpendicular outer EVPAs plus a new superluminal component near the IceCube neutrino detection.
Exact Schwarzschild and Kerr geometries in a disformally related frame yield secondary disformal scalar hair on black holes in a projectively invariant scalar-torsion theory.
citing papers explorer
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A Jet from a Nearly Dormant Black Hole
Multi-frequency VLBI observations detect a two-sided jet with steep synchrotron spectrum from the nearly dormant SMBH in M60, with frequency-dependent core shift locating the engine ~10 Schwarzschild radii upstream of the 8.37 GHz core.
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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.
-
Constitutive birefringence and critical curves in the rotating Garc\'ia--D\'iaz black hole
In the rotating García-Díaz NLED black hole the Fresnel quartic factorizes into two optical metrics whose critical families project to distinct contours Γ+ and Γ- whose angular separation is generated by the constitutive response and redistributed by spin.
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Measuring a Black Hole's Area Immediately after Merger: A Direct-Wave Test of Hawking's Area Law
A gravitational-wave method infers the Kerr-equivalent horizon area from direct waves in the near-merger signal of GW250114, yielding consistency with the Kerr remnant and a new test of Hawking's area law.
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Photon spheres in dynamical space-times
A covariant framework is developed for photon surfaces in dynamical spherical spacetimes, recovering static limits and applied to collapse and accretion/evaporation models.
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Rapidly Rotating Neutron Star Collapse in Massive Scalar-Tensor Theories
In massive scalar-tensor gravity, rotating neutron stars that collapse emit nearly the same tensor gravitational waves as in general relativity, but lose about 10^-3 solar masses of energy in scalar radiation - far more than the quadrupole channel.
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Spin-Induced Nonlinear Scalarization of Kerr Black Holes in Einstein-scalar-Gauss-Bonnet Gravity
Kerr black holes in an EsGB model without linear instability undergo nonlinear scalarization above spin 0.5, existing in a finite low-mass high-spin wedge rather than a narrow band.
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GRMHD accretion beyond the black hole paradigm: Light from within the shadow
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
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Analog regular black holes and black hole mimickers for surface-gravity waves in fluids
Surface-gravity waves in shallow water can be configured with central and graded drainage to analogize regular black holes and mimickers, enabling lab study of their instabilities.
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Kinetic magnetohydrodynamics and Landau fluid closure in relativity
The authors derive relativistic drift-kinetic moment equations and a new analytic Landau fluid closure that incorporates anisotropic heat conduction and Landau damping without assuming collisional thermalization.
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Strong-deflection expansion of the deflection angle near a degenerate photon sphere
Derives a factorized leading term for the strong deflection angle near degenerate photon spheres using local expansion of the effective potential and Weyl tensor measures.
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Scattering from compact objects: Debye series and Regge-Debye poles
An exact Debye-series decomposition of the scattering matrix for waves on compact stars reveals distinct Regge-Debye pole families that dominate amplitudes differently in neutron-star-like and ultracompact regimes.
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Shadows of Giants: Constraints on Stupendously Large Black Holes from Negative Sources against the Cosmic Microwave Background
Stupendously large black holes cast shadows on the CMB that rule out masses above 10^17 solar masses within the last scattering surface and limit their density parameter to below 10^-5 for masses 10^15 to 10^18 solar masses.
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Rotating Black Holes with Primary Scalar Hair: Shadow Signatures in Beyond Horndeski Gravity
Rotating black holes with primary scalar hair in beyond Horndeski gravity produce shadows whose diameter increases for negative Q and whose distortion increases for positive Q, with EHT bounds on M87* restricting but not ruling out the (a, Q) parameter space.
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Charged Superradiant Instability of Spherically Symmetric Regular Black Holes in de Sitter Spacetime: Time- and Frequency-Domain Analysis
ABG-dS black holes show charged superradiant instability exclusively for the spherically symmetric ℓ=0 mode, with growth rates that peak at intermediate Λ and q and rise with Q, differing from RN-dS due to nonlinear electrodynamics.
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Black hole mergers beyond general relativity: a self-force approach
Self-force theory is extended to compute merger and ringdown waveforms in beyond-GR black hole binaries under the extreme mass-ratio approximation, with first calculations of self-force corrections to the merger waveform.
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Topological charge and black hole photon spheres in massive gravity
In dRGT massive gravity, static spherically symmetric black holes exhibit zero, one, or two photon spheres whose topological charges and stability patterns differ from Einstein gravity and from horizonless compact objects.
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Regular Vaidya solutions of effective gravitational theories
Regular Vaidya solutions exist in effective gravitational theories that dynamically describe radiation-driven formation of regular black holes or mimickers without curvature singularities.
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Neutron stars more compact than black holes as a probe of strong-field gravity
Stable neutron-star configurations denser than black holes exist in quasi-topological gravity and may produce detectable gravitational-wave echoes.
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VAPOLA -- A multi-year, multi-band polarization survey of AGN and Sgr A* at mm wavelengths with ALMA I. Survey Overview and Science-Ready Archival Products
VAPOLA releases multi-epoch multi-band ALMA full-Stokes products and polarimetric fits for AGN and Sgr A* via an automated pipeline and web portal.
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Polarization Architecture of Steady GRMHD Jets from the Horizon to Infinity
Steady GRMHD jets exhibit a universal near-horizon polarization pattern set only by black hole spin, with large-radius polarization angle following a collimation-determined power law and intermediate scales modified by plasma loading.
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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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Parsec-scale polarimetry and kinematics of a spine-sheath jet in the neutrino-blazar TXS 0506+056
VLBI observations of TXS 0506+056 show a spine-sheath jet with aligned inner and perpendicular outer EVPAs plus a new superluminal component near the IceCube neutrino detection.
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Nonrotating and rotating black holes with secondary disformal hair in a ghost-free metric-affine parity-violating scalar-torsion theory
Exact Schwarzschild and Kerr geometries in a disformally related frame yield secondary disformal scalar hair on black holes in a projectively invariant scalar-torsion theory.
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Photon surfaces extension in general spherical dust collapse
In general LTB dust collapse the photon surface is a null hypersurface generated by outgoing radial null geodesics that reaches the central singularity if and only if the singularity is naked.
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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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Absorption cross section of a Schwarzschild black hole for a massive vector field
Numerical computation of absorption cross sections for massive Proca fields on Schwarzschild black holes, revealing mass-induced longitudinal modes and breaking of even-odd parity degeneracy in transmission spectra.
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Quasinormal modes and tidal responses of black holes in generic anisotropic matter environments
A perturbative framework for black holes in anisotropic matter shows quasinormal modes dominated by gravitational redshift while tidal Love numbers exhibit order-unity deviations including vanishing and negative values.
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Curvature-induced scalarization of charged AdS black holes
The Breitenlohner-Freedman bound restricts Gauss-Bonnet scalarization of RN-AdS black holes to a single fundamental branch for 0<η<2.25, with a separate single branch for η<0.
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Ces\`aro convergence of the high-order WKB method and its applications to black-hole overtones and long-lived modes
High-order WKB with Padé approximants and Cesàro means enables computation of black-hole overtones and long-lived quasinormal modes, with a noted limitation that apparent convergence can be incorrect for some metrics.
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Neutron stars more compact than black holes in quasi-topological gravity: Equilibrium configurations and radial stability
Neutron stars in quasi-topological gravity can be more compact than black holes and radially stable across several equations of state.
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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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A metric solution for rotating black holes embedded in dark matter halos with central spikes
A rotating black-hole metric with a dark-matter halo is derived, but the proposed halo profiles do not make the spacetime asymptotically flat as claimed.
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Demagnetizing KBR and New Ricci-flat Rotating Metric
A new Ricci-flat rotating metric is obtained by demagnetizing the KBR solution, yielding a deformed Kerr geometry with non-flat asymptotics for which black hole thermodynamics is established.
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A Complete Invariant Analysis of the Kerr Spacetime and its Photon Region
An invariant function is derived whose zeros identify spherical photon orbits in Kerr spacetime, parameterized by an inclination angle, enabling invariant characterization of the photon region and constants of motion.
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Reshaping the inner shadow of a Kerr black hole by a torn accretion disk
Torn accretion disks around Kerr black holes erode the inner shadow and produce bifurcated, crescent, and multi-order ring morphologies hard to obtain with standard equatorial disks.
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Regular Black Holes in General Relativity from Nonlinear Electrodynamics with de Sitter Cores
Two new regular black-hole solutions with de Sitter cores, supported by magnetic nonlinear electrodynamics, are constrained by Sgr A* shadows and shown to be linearly stable under scalar perturbations.
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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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Relative Magnification Factor of Point Sources on Accretion Disks
Corotating point sources on accretion disks near black holes distort the relative magnification factor distribution, modulating caustics and encoding accretion flow kinematics via time-delayed images.
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Gravity/thermodynamics correspondence via black hole shadows
Cuspy black hole shadows correspond to swallowtail thermodynamic free energy, with boundary self-intersections marking geometric phase transitions whose critical exponents fall in the mean-field class.
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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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Cosmological coupled black holes immersed in dark sector
Derives an exact solution for a black hole in anisotropic dark sector FLRW background with mass co-evolving via radius-dependent coupling governed by the dark halo profile.
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Shadows of quintessence black holes: spherical accretion, photon trajectories, and geodesic observers
Quintessence black holes produce observer-dependent shadow angular sizes, with infalling observers seeing smaller shadows than static ones, yielding stronger equation-of-state constraints from M87* observations.
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On the Cuspy Structure of Rotating Wormhole Shadows
Rotating wormhole shadows develop cusps above a universal critical redshift value λ_c, yielding four morphologies: smooth, cuspy, ears touching, and throat drowning.
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Parameterized Post-Newtonian Analysis of Quadratic Gravity and Solar System Constraints
Quadratic gravity with Weyl-squared and Ricci-squared terms produces PPN parameters that equal their GR values except for exponentially decaying corrections, with gamma identically 1 when the two mode masses are equal, yielding solar-system lower bounds m_R, m_W greater than or equal to 23 per AU.
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Bounds on the photon sphere radius for spherically symmetric black holes in n-dimensional Einstein gravity
Upper bound r_γ ≤ [(n-1)M]^{1/(n-3)} and lower bound r_γ ≥ ((n-1)/2)^{1/(n-3)} r_H on the photon sphere for nD black holes with anisotropic matter obeying the weak energy condition and non-positive trace.
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Black Hole Spectroscopy and Tests of General Relativity with GW250114
GW250114 data confirm the remnant is consistent with a Kerr black hole and bound the dominant quadrupolar mode frequency to within a few percent of the GR prediction, with constraints tighter than prior multi-event catalogs.
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An analytic model for a total process of gravitational collapse: From star to Schwarzschild black hole
An exact spherically symmetric analytic collapse model grows an apparent horizon H(t) from zero to 2M while hiding an integrable central singularity and preserving weak cosmic censorship without exotic matter.
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Observational Limits on Einasto Dark Matter Parameters from Event Horizon Telescope Images of Sgr A$^{*}$ and M87$^{*}$
EHT dimensionless shadow diameters plus stellar-dynamical mass priors constrain Einasto central density to ρ₀ ≲ 10^{-11} M⊙/pc³ (1σ) for Sgr A*, with weaker bounds for M87*.
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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.