First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric

Abstract

Astrophysical black holes are expected to be described by the Kerr metric. This is the only stationary, vacuum, axisymmetric metric, without electromagnetic charge, that satisfies Einstein's equations and does not have pathologies outside of the event horizon. We present new constraints on potential deviations from the Kerr prediction based on 2017 EHT observations of Sagittarius A* (Sgr A*). We calibrate the relationship between the geometrically defined black hole shadow and the observed size of the ring-like images using a library that includes both Kerr and non-Kerr simulations. We use the exquisite prior constraints on the mass-to-distance ratio for Sgr A* to show that the observed image size is within $\sim$ 10$\%$ of the Kerr predictions. We use these bounds to constrain metrics that are parametrically different from Kerr as well as the charges of several known spacetimes. To consider alternatives to the presence of an event horizon we explore the possibility that Sgr A* is a compact object with a surface that either absorbs and thermally re-emits incident radiation or partially reflects it. Using the observed image size and the broadband spectrum of Sgr A*, we conclude that a thermal surface can be ruled out and a fully reflective one is unlikely. We compare our results to the broader landscape of gravitational tests. Together with the bounds found for stellar mass black holes and the M87 black hole, our observations provide further support that the external spacetimes of all black holes are described by the Kerr metric, independent of their mass.

55 pages, 27 figures, published in The Astrophysical Journal Letters on May 12, 2022. See the published paper for the full authors list

References in corpus (68)

• The Confrontation between General Relativity and Experiment
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Strong constraints on cosmological gravity from GW170817 and GRB 170817A
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Black Hole Shadows, Photon Rings, and Lensing Rings
• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• An Update on Monitoring Stellar Orbits in the Galactic Center
• Advection-Dominated Accretion and the Black Hole Event Horizon
• First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole
• Notes on non-singular models of black holes
• A Metric for Rapidly Spinning Black Holes Suitable for Strong-Field Tests of the No-Hair Theorem
• First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• Constraints on black-hole charges with the 2017 EHT observations of M87*
• Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
• A new method for shadow calculations: application to parameterised axisymmetric black holes
• How to tell a gravastar from a black hole
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits
• Testing General Relativity with stellar orbits around the supermassive black hole in our Galactic center
• Strong-field Gravity Tests with the Double Pulsar
• The structure of the nuclear stellar cluster of the Milky Way
• The Shadow of a Spherically Accreting Black Hole
• New parametrization for spherically symmetric black holes in metric theories of gravity
• Thin accretion disks in stationary axisymmetric wormhole spacetimes
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Improved GRAVITY astrometric accuracy from modeling of optical aberrations
• Polarimetry of near-infrared flares from Sagittarius A*
• Linking Tests of Gravity On All Scales: from the Strong-Field Regime to Cosmology
• Bumpy Black Holes in Alternate Theories of Gravity
• Observable Properties of Orbits in Exact Bumpy Spacetimes
• A Constant Spectral Index for Sagittarius A* During Infrared/X-ray Intensity Variations
• Kerr Black Holes are Not Unique to General Relativity
• The Disc-Jet Symbiosis Emerges: Modeling the Emission of Sagittarius A* with Electron Thermodynamics
• Radio and Millimeter Monitoring of Sgr A*: Spectrum, Variability, and Constraints on the G2 Encounter
• Asymptotic safety casts its shadow
• Sgr A* near-infrared flares from reconnection events in a magnetically arrested disc
• Ab Initio Horizon-Scale Simulations of Magnetically Arrested Accretion in Sagittarius A* Fed by Stellar Winds
• Perturbed Kerr Black Holes can probe deviations from General Relativity
• Where are all the gravastars? Limits upon the gravastar model from accreting black holes
• Evaluation of New Submillimeter VLBI Sites for the Event Horizon Telescope
• On the nature of the fast moving star S2 in the Galactic Center
• The Event Horizon of M87
• Fermi Bubbles Inflated by Winds Launched from the Hot Accretion Flow in Sgr A*
• Broad K$\alpha$ iron line from accretion disks around traversable wormholes
• Dynamically important magnetic fields near the event horizon of Sgr A*
• ALMA and VLA measurements of frequency-dependent time lags in Sagittarius A*: evidence for a relativistic outflow
• Constraining particle acceleration in Sgr A* with simultaneous GRAVITY, Spitzer, NuSTAR and Chandra observations
• The X-ray Flux Distribution of Sagittarius A* as Seen by Chandra
• The Flux Distribution of Sgr A*
• Search for a Variation of the Fine Structure around the Supermassive Black Hole in Our Galactic Center
• Distinguishing gravitational and emission physics in black-hole imaging: spherical symmetry
• Test of Einstein equivalence principle near the Galactic center supermassive black hole
• Accurate mapping of spherically symmetric black holes in a parameterised framework
• Spitzer/IRAC Observations of the Variability of Sgr A* and the Object G2 at 4.5 microns
• Detection of faint stars near SgrA* with GRAVITY
• Probing beyond-Kerr spacetimes with inspiral-ringdown corrections to gravitational waves
• The Galactic Center: An Improved Astrometric Reference Frame for Stellar Orbits around the Supermassive Black Hole
• The Galactic Center: Improved Relative Astrometry for Velocities, Accelerations, and Orbits near the Supermassive Black Hole
• Sagittarius A* High Energy X-ray Flare Properties During NuSTAR Monitoring of the Galactic Center from 2012 to 2015
• Second Scale Submillimeter Variability of Sagittarius A* during flaring activity of 2019: On the Origin of Bright Near Infrared Flares
• Exact theory for the Rezzolla-Zhidenko metric and self-consistent calculation of quasinormal modes
• MeqSilhouette v2: Spectrally-resolved polarimetric synthetic data generation for the Event Horizon Telescope
• On the prospects of imaging Sagittarius A* from space

Cited by in corpus (145)

• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• Key Science Goals for the Next-Generation Event Horizon Telescope
• Millimeter light curves of Sagittarius A* observed during the 2017 Event Horizon Telescope campaign
• Testing Rotating Regular Metrics with EHT Results of Sgr A*
• The Science of the Einstein Telescope
• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• Shadows of black holes with dark matter halo
• Testing strong gravitational lensing effects by supermassive compact objects with regular spacetimes
• The Image of the M87 Black Hole Reconstructed with PRIMO
• Shape of higher-order images of equatorial emission rings around a Schwarzschild black hole: Analytical description with polar curves
• A review on analytical studies in Gravitational Lensing
• Gravity experiments with radio pulsars
• Deflection angle and shadow of the Reissner-Nordström black hole with higher-order magnetic correction in Einstein-nonlinear-Maxwell fields
• Hunting extra dimensions in the shadow of Sgr A*
• Kerr-MOG-(A)dS black hole and its shadow in scalar-tensor-vector gravity theory
• Images of hairy Reissner-Nordström black hole illuminated by static accretions
• Towards VLBI Observations of Black Hole Structure
• Selective Dynamical Imaging of Interferometric Data
• Influence of accretion disk on the optical appearance of the Kazakov-Solodukhin black hole
• Trinity of black hole correspondences: Shadows, quasinormal modes, graybody factors, and cautionary remarks
• EHT observables as a tool to estimate parameters of supermassive black holes
• Probing spacetime and accretion model for the Galactic Center: Comparison of Kerr and dilaton black hole shadows
• Neutron stars as extreme laboratories for gravity tests
• Bayesian Accretion Modeling: Axisymmetric Equatorial Emission in the Kerr Spacetime
• Exploring Nonlinear Electrodynamics Theories: Shadows of Regular Black Holes and Horizonless Ultra-Compact Objects
• Parameter constraints on a black hole with Minkowski core through quasiperiodic oscillations
• Gaussian tripartite steering in Schwarzschild black hole
• Enabling Transformational ngEHT Science via the Inclusion of 86 GHz Capabilities
• M87: a cosmic laboratory for deciphering black hole accretion and jet formation
• Note on fundamental physics tests from black hole imaging: Comment on "Hunting for extra dimensions in the shadow of Sagittarius A${}^{\ast }$"
• Kerr black hole in de Sitter spacetime and observational redshift: Toward a new method to measure the Hubble constant
• Rotating Black Hole in Kalb-Ramond Gravity: Constraining Parameters by Comparison with EHT Observations of Sgr A* and M87*
• Black Holes Up Close
• Loop Quantum Gravity motivated multihorizon rotating black holes
• A Characterization of the ALMA Phasing System at 345 GHz
• GUP-corrected black holes: Thermodynamic properties, evaporation time and shadow constraint from EHT Observations of M87* and Sgr A*
• Proca theory of four-dimensional regularized Gauss-Bonnet gravity and black holes with primary hair
• Shadow thermodynamics of non-linear charged Anti-de Sitter black holes
• Equilibrium non-selfgravitating tori around black holes in parameterised spherically symmetric spacetimes
• Thermodynamics, Weak Gravitational Lensing, and Parameter Estimation of a Schwarzschild Black Hole Immersed in Hernquist Dark Matter Halo
• The Influence of Uniform Magnetic Fields on Strong Field Gravitational Lensing by Kerr Black Holes
• Shadow thermodynamics of the Hayward-AdS black hole
• The future ability to test theories of gravity with black-hole shadows
• Orbital configurations of spaceborne interferometers for studying photon rings of supermassive black holes
• Non-commutativity in Hayward spacetime
• Constructing noncommutative black holes
• Shadows and quasinormal modes of a charged non-commutative black hole by different methods
• Shadow behavior of an EMSG charged black hole
• Traces of quantum gravitational correction at third-order curvature through the black hole shadow and particle deflection at the weak field limit
• Exploring departures from Schwarzschild black hole in $f(R)$ gravity
• Thin accretion disk images of the black hole in symmergent gravity
• Parameter estimation of Kerr-Bertotti-Robinson black holes using their shadows
• Optical appearance of numerical black hole solutions in higher derivative gravity
• The Next Generation Event Horizon Telescope Collaboration: History, Philosophy, and Culture
• Gravitational signatures of a nonlinear electrodynamics in $f(R,T)$ gravity
• Spins of supermassive black holes M87* and SgrA* revealed from the size of dark spots in Event Horizon Telescope Images
• A first search of transients in the Galactic Center from 230 GHz ALMA observations
• Hunting for extra dimensions in black hole shadows
• Exploring the shear viscosity in four-dimensional planar black holes beyond General Relativity
• Free-falling test particles in a charged Kalb-Ramond black hole: gravitational Doppler effect and tidal forces
• Interferometric signature of higher-order images in a parametrized framework
• Probing loop quantum effects through solar system experiments: observational signatures and parameter constraints
• Assessing the stability of ultracompact spinning boson stars with nonlinear evolutions
• Multimodal signatures of asymptotic (A)dS Kalb-Ramond black holes: Constraints through the shadow, weak deflection angle, and topological photon spheres
• First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA
• General Relativistic effects and the NIR variability of Sgr A* II: A systematic approach to temporal asymmetry
• Imaging fermionic dark matter cores at the center of galaxies
• Optical appearance of the Schwarzschild black hole in the string cloud context
• Particle dynamics and optical appearance of charged spherically symmetric black holes in bumblebee gravity
• Black Holes in Lorentz-Violating Gravity: Thermodynamics, Geometry, and Particle Dynamics
• Deep learning inference with the Event Horizon Telescope II. The Zingularity framework for Bayesian artificial neural networks
• Kerr-scalaron metric and astronomical consequences near the Galactic Center black hole
• Deep learning inference with the Event Horizon Telescope I. Calibration improvements and a comprehensive synthetic data library
• Strong gravitational lensing effects around rotating regular black holes
• Probing Accretion Turbulence in the Galactic Center with EHT Polarimetry
• Fractal signatures of non-Kerr spacetimes in the shadow of light-ring bifurcations
• Signatures of Einstein-Maxwell dilaton-axion gravity from the observed quasi-periodic oscillations in black holes
• Rotating scalarized black holes: the role of the coupling
• Quantumness near the Schwarzschild black hole based on W-state
• Synchrotron emitting Komissarov torus with magnetic polarization around Kerr black holes
• Quantum parameter-mass induced scalarization of qOS-black hole in the Einstein-Gauss-Bonnet-scalar theory
• Overlapping of photon rings in black hole imaging
• Not all spacetime coordinates for general-relativistic ray tracing are created equal
• Galaxy dynamics tracing quantum cosmology beyond $\Lambda$CDM below the de Sitter scale of acceleration
• Impact of the nonthermal electron radiation effects on the horizon scale image structure of Sagittarius A*
• Probing a Lorentz-violating parameter from orbital precession of the S2 star around the galactic centre supermassive black hole
• Non-thermal Synchrotron Emission and Polarization Signatures during Black Hole Flux Eruptions
• Sgr A* Shadow Study with KTN Space Time and Investigation of NUT Charge Existence
• Synthetic gravitational lens image of the Sagittarius A${}^{\ast }$ black hole with a thin disk model
• Observable strong field effects of extra spacetime dimension in the braneworld black hole
• Testing black hole space-times with the S2 star orbit: a Bayesian comparison
• Regular black hole solutions in $(2+1)$-dimensional $f(R,T)$ gravity coupled to nonlinear electrodynamics
• Imprints of non-commutativity on charged black holes
• Limiting the Yukawa Gravity through the Black Hole Shadows of Sgr A* and M87*
• Gravitational lensing inside and outside of a marginally unstable photon sphere in a general, static, spherically symmetric, and asymptotically-flat spacetime in strong deflection limits
• Limits on the existence of totally reflective exotic compact objects with current and future gravitational-wave detectors
• Constructing Regular Lovelock Black Holes with degenerate vacuum and $\Lambda <0$, using the gravitational tension. Shadow analysis
• Probing Observable Features of Lorentz violation in Low-Energy Hořava Gravity with Accretion Disk Images of Black Hole
• Ten years of extreme gravity tests of general theory of relativity with gravitational-wave observations
• Gravitational wave pulse and memory effects for hairy Kiselev black hole and its analogy with Bondi-Sachs formalism
• Spin Precession in magnetized Kerr spacetime
• Regular Black Hole Cores via Gravitational Evanescence of Collapsing Matter
• Deciphering signatures of Kerr-Sen black holes in presence of plasma from the Event Horizon Telescope data
• Absorption and scattering of a high dimensional noncommutative black hole
• Characterization of black hole accretion through image moment invariants
• Noncommutative information is revealed from the static detector outside the black hole
• Stability of the spacetime of a magnetized compact object
• Iterative Relaxation Method to Obtain Global Transonic Flows around Compact Objects
• Charge constraint on M87* with twisted light
• Some perspective of thermodynamical and optical properties of black holes in Maxwell-dilaton-dRGT-like massive gravity
• Energy conditions in static, spherically symmetric spacetimes and effective geometries
• Shadow of rotating black holes with consistent thermodynamics
• Formation of gravastars
• Thermodynamic and observational implications of black holes in toroidal geometry
• Shadows cast by a class of rotating black bounces with an anisotropic fluid
• Quantum-Corrected Thermodynamics of Conformal Weyl Gravity Black Holes: GUP Effects and Phase Transitions
• Exploring black holes with multiple photon spheres by interferometric signatures
• Black holes and wormholes in Deser-Woodard gravity
• Perturbations of Einstein--Maxwell--phantom spacetime: Instabilities of charged Ellis--Bronnikov wormholes and quasinormal modes of black holes
• Exploring black hole shadows in axisymmetric spacetimes with coordinate-independent methods and neural networks
• Shadow constraints of charged black hole with scalar hair and gravitational waves from extreme mass ratio inspirals
• Gravitational wave memory in wormhole spacetimes
• Images of the accretion disk in Hybrid metric-Palatini gravity
• Testing General Relativity with Black Holes
• Comment on "Strong lensing and shadow of Ayon-Beato-Garcia (ABG) nonsingular black hole"
• Scattering of massive particles from black holes and naked singularities
• Investigating the interplay of the braneworld gravity and the plasma environment on the black hole shadow
• Parameter Inference of Black Hole Images using Deep Learning in Visibility Space
• Macroscopic backreaction of the trace anomaly on classical vacuum backgrounds
• Optical appearance of regularized compact objects without an exterior photon sphere
• Searching for Isolated Black Hole Candidates within 15 pc of the Solar System in Gaia DR3
• Spacetime of rotating black holes surrounded by massive scalar charges
• Universality of the Blandford-Znajek emission in stationary and axisymmetric spacetimes
• Scattering from compact objects: Debye series and Regge-Debye poles
• Shaving off soft hairs and the black hole image memory effect
• Improved Constraints on Non-Kerr Deviations from Binary Black Hole Inspirals Using GWTC-4 Data
• Observational distinguishability of the Kerr and Kerr-Hayward metrics to EHT
• Electromagnetic emission from a black-to-white hole transition -- Photospheric emission
• Relativistic Thermal Emission from Accretion Disks in Kerr-MOG Spacetimes
• Thin accretion disks around a Schwarzschild acoustic black hole
• Multiobjective optimization for scattering mitigation and scattering screen reconstruction in VLBI observations of the Galactic Center
• Sagittarius A* near-infrared flares polarization as a probe of space-time I: Non-rotating exotic compact objects