Testing the Schwarzschild metric in a strong field region with the Event Horizon Telescope

Abstract

Testing gravity theory in the strong field region becomes a reality due to the observations of gravitational waves and black hole shadows. In this paper, we discuss how to constrain the possible deviations of the classical general relativity with the image of M87* observed by the Event Horizon Telescope. More precisely, we want to know where is the event horizon for a non-rotating black hole. General relativity predicts the horizon is located at the Schwarzschild radius $r_{\text{s}}$, while other gravity theories may give different predictions. We propose a parameterized Schwarzschild metric (PSM) in which the horizon is located at $r=n{r}_{\text{s}}$, where $n$ is a real free parameter, and prove general relativity with nonlinear electrodynamics allows $n\ne 1$. In the weak field region, the PSM is equivalent to the Schwarzschild metric regardless of the value of $n$. In the strong field region, the difference between the PSM and Schwarzschild metric would leave an imprint on the shadow image. We present detailed calculations and discussions on the black hole shadows with large background light source and accretion disk in the PSM framework. More importantly, we point out that $n\approx 2$ can be used to explain why the black hole mass measured by the shadow is a factor of about two larger than the previous gas dynamics measurements. If this explanation is confirmed to be right, then this phenomenon, together with the late-time cosmological acceleration, will be very important to test gravity theories.

14 pages, 9 figures, PRD accepted

References in corpus (112)

• f(R) Theories Of Gravity
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Modified Gravity and Cosmology
• The Confrontation between General Relativity and Experiment
• f(R) theories
• Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
• Tests of general relativity with GW150914
• 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
• Beyond the Cosmological Standard Model
• Viewing the Shadow of the Black Hole at the Galactic Center
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• Dark Energy after GW170817: dead ends and the road ahead
• The Bardeen Model as a Nonlinear Magnetic Monopole
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Strong constraints on cosmological gravity from GW170817 and GRB 170817A
• Dark Energy after GW170817 and GRB170817A
• Implications of the Neutron Star Merger GW170817 for Cosmological Scalar-Tensor Theories
• Foundations of Black Hole Accretion Disk Theory
• Tests of General Relativity with GW170817
• Shadows of Kerr black holes with scalar hair
• The Black-Hole Mass in M87 from Gemini/NIFS Adaptive Optics Observations
• Jet Launching Structure Resolved Near the Supermassive Black Hole in M87
• Photon Regions and Shadows of Kerr-Newman-NUT Black Holes with a Cosmological Constant
• The supermassive black hole of M87 and the kinematics of its associated gaseous disk
• Hunting for extra dimensions in the shadow of M87*
• Shadow of a black hole surrounded by dark matter
• Solar System constraints to general f(R) gravity
• A new method for shadow calculations: application to parameterised axisymmetric black holes
• The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project
• The M87 Black Hole Mass from Gas-dynamical Models of Space Telescope Imaging Spectrograph Observations
• Mapping spacetimes with LISA: inspiral of a test-body in a `quasi-Kerr' field
• The Newtonian Limit of F(R) gravity
• The Black Hole Mass, Stellar M/L, and Dark Halo in M87
• The Current Ability to Test Theories of Gravity with Black Hole Shadows
• Spontaneously scalarised Kerr black holes
• The Black Hole Accretion Code
• Non-Spinning Black Holes in Alternative Theories of Gravity
• Black hole shadow in an asymptotically-flat, stationary, and axisymmetric spacetime: The Kerr-Newman and rotating regular black holes
• Shadow of a Kaluza-Klein rotating dilaton black hole
• New parametrization for spherically symmetric black holes in metric theories of gravity
• Testing the No-Hair Theorem with Event Horizon Telescope Observations of Sagittarius A*
• A Fast New Public Code for Computing Photon Orbits in a Kerr Spacetime
• Shadow cast and Deflection angle of Kerr-Newman-Kasuya spacetime
• Ultra Light Boson Dark Matter and Event Horizon Telescope Observations of M87*
• Shadow of Kerr-Taub-NUT black hole
• Black Hole Surrounded by a Dark Matter Halo in the M87 Galactic Center and its Identification with Shadow Images
• Speed of Gravitational Waves and the Fate of Scalar-Tensor Gravity
• GYOTO: a new general relativistic ray-tracing code
• Black hole shadow in a general rotating spacetime obtained through Newman-Janis algorithm
• Fundamental photon orbits: black hole shadows and spacetime instabilities
• GW170817 Falsifies Dark Matter Emulators
• Shadows of rotating wormholes
• Generalized framework for testing gravity with gravitational-wave propagation. II. Constraints on Horndeski theory
• Parabolic Jets from the Spinning Black Hole in M87
• Limits on the number of spacetime dimensions from GW170817
• Vainshtein mechanism after GW170817
• Brane-world extra dimensions in light of GW170817
• Constraints on Einstein-aether theory after GW170817
• Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole
• $f(T)$ gravity after GW170817 and GRB170817A
• Rotating Black Hole Shadow in Perfect Fluid Dark Matter
• Accretion Processes On a Black Hole
• Asymptotic safety casts its shadow
• The fate of large-scale structure in modified gravity after GW170817 and GRB170817A
• Analytical representation for metrics of scalarized Einstein-Maxwell black holes and their shadows
• Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk
• Constraining nonperturbative strong-field effects in scalar-tensor gravity by combining pulsar timing and laser-interferometer gravitational-wave detectors
• Does the black hole shadow probe the event horizon geometry?
• Hořava Gravity after GW170817
• Alive and well: mimetic gravity and a higher-order extension in light of GW170817
• Regular Multi-Horizon Black Holes in Modified Gravity with Non-Linear Electrodynamics
• Astrophysical imaging of Kerr black holes with scalar hair
• Polarization-based Tests of Gravity with the Stochastic Gravitational-Wave Background
• Dark energy after GW170817, revisited
• Looking for ultralight dark matter near supermassive black holes
• Observational signature of near-extremal Kerr-like black holes in a modified gravity theory at the Event Horizon Telescope
• Shadows of Kerr-like black holes in a modified gravity theory
• Regular black holes in $f(R)$ gravity coupled to nonlinear electrodynamics
• Cosmological Constraints on Horndeski Gravity in Light of GW170817
• RAPTOR I: Time-dependent radiative transfer in arbitrary spacetimes
• Shadows of Bonnor black dihole by chaotic lensing
• Simulations of imaging the event horizon of Sagittarius A* from space
• Chaotic shadow of a non-Kerr rotating compact object with quadrupole mass moment
• Black Hole Shadow as a Test of General Relativity: Quadratic Gravity
• Testing General Relativity with Accretion-Flow Imaging of Sgr A*
• Constraining spins of supermassive black holes from TeV variability. II. fully general relativistic calculations
• YNOGK: A new public code for calculating null geodesics in the Kerr spacetime
• Constraints on Hořava gravity from binary black hole observations
• A note on singular and non-singular black holes
• Neutron star merger GW170817 strongly constrains doubly coupled bigravity
• Cosmological Bound from the Neutron Star Merger GW170817 in scalar-tensor and $F(R)$ gravity theories
• Constraints on $f(R)$ theories of gravity from GW170817
• Fast-spinning black holes inferred from symmetrically limb-brightened radio jets
• The brightest point in accretion disk and black hole spin: implication to the image of black hole M87*
• Observing supermassive black holes in virtual reality
• Exploring strong-field deviations from general relativity via gravitational waves
• Regular multihorizon black holes in $f(G)$ gravity with nonlinear electrodynamics
• The Spin of M87*
• Black Hole Spin Signature in the Black Hole Shadow of M87 in the Flaring State
• Comments on "Solar System constraints to general f(R) gravity"
• GRay2: A General Purpose Geodesic Integrator for Kerr Spacetimes
• Astrophysical Signatures of Black holes in Generalized Proca Theories
• Gravity in mimetic scalar-tensor theories after GW170817
• Probing spacetime around Sagittarius A* using modeled VLBI closure phases
• Experimental Relativity with Accretion Disk Observations
• Newtonian approximation and possible time-varying $G$ in nonlocal gravities
• Scalar-tensor nonlocal gravity
• Constraints on Black Hole Jet Models Used As Diagnostic Tools of Event Horizon Telescope Observations of M87
• 4G: Pure fourth-order gravity

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• Quasinormal modes, stability and shadows of a black hole in the 4D Einstein-Gauss-Bonnet gravity
• Silhouette of M87*: A new window to peek into the world of hidden dimensions
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• Testing the equivalence principle via the shadow of black holes
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• Testing the nature of Gauss-Bonnet gravity by four-dimensional rotating black hole shadow
• The shadow of M87* black hole within rational nonlinear electrodynamics
• Silhouettes of invisible black holes
• Does the shape of the shadow of a black hole depend on motional status of an observer?
• Black hole shadow in the view of freely falling observers
• Image of the Schwarzschild black hole pierced by a cosmic string with a thin accretion disk
• The observer-dependent shadow of the Kerr black hole
• New test on the Einstein equivalence principle through the photon ring of black holes
• Tidal forces in parametrized spacetime: Rezzolla-Zhidenko parametrization
• Optical appearance of numerical black hole solutions in higher derivative gravity
• Motion of particles around a magnetically charged Euler-Heisenberg black hole with scalar hair and the Event Horizon Telescope
• Image of the time-dependent black hole
• Visible shapes of black holes M87* and SgrA*
• Images of the accretion disk in Hybrid metric-Palatini gravity