A General Relativistic Null Hypothesis Test with Event Horizon Telescope Observations of the black-hole shadow in Sgr A*

Abstract

The half opening angle of a Kerr black-hole shadow is always equal to (5+-0.2)GM/Dc^2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within this 4% range constitutes a null hypothesis test of General Relativity. We show that the black hole in the center of the Milky Way, Sgr A*, is the optimal target for performing this test with upcoming observations using the Event Horizon Telescope. We use the results of optical/IR monitoring of stellar orbits to show that the mass-to-distance ratio for Sgr A* is already known to an accuracy of +-4%. We investigate our prior knowledge of the properties of the scattering screen between Sgr A and the Earth, the effects of which will need to be corrected for in order for the black-hole shadow to appear sharp against the background emission. Finally, we explore an edge detection scheme for interferometric data and a pattern matching algorithm based on the Hough/Radon transform and demonstrate that the shadow of the black hole at 1.3 mm can be localized, in principle, to within ~9%. All these results suggest that our prior knowledge of the properties of the black hole, of scattering broadening, and of the accretion flow can only limit this General Relativistic null hypothesis test with Event Horizon Telescope observations of Sgr A* to 10%.

To appear in the Astrophysical Journal

References in corpus (17)

• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• Apparent shape of super-spinning black holes
• Shadow of a Kaluza-Klein rotating dilaton black hole
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• Kerr black hole lensing for generic observers in the strong deflection limit
• Observational appearance of inefficient accretion flows and jets in 3D GRMHD simulations: Application to Sgr~A*
• Shape and position of the shadow in the $\delta =2$ Tomimatsu-Sato space-time
• Plasma diagnostic potential of 2p4f in N${}^{+}$ -- accurate wavelengths and oscillator strengths
• The Power of Imaging: Constraining the Plasma Properties of GRMHD Simulations using EHT Observations of Sgr A*
• Towards the event horizon -- the supermassive black hole in the Galactic Center
• Theory and Simulations of Refractive Substructure in Resolved Scatter-Broadened Images
• Imaging an Event Horizon: Mitigation of Scattering Toward Sagittarius A*
• Fast Variability and mm/IR flares in GRMHD Models of Sgr A* from Strong-Field Gravitational Lensing
• Event-Horizon-Telescope Evidence for Alignment of the Black Hole in the Center of the Milky Way with the Inner Stellar Disk
• The Intrinsic Two-Dimensional Size of Sagittarius A*
• Discovery of Substructure in the Scatter-Broadened Image of Sgr A*
• Using Millimeter VLBI to Constrain RIAF Models of Sagittarius A*

Cited by in corpus (98)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• Black holes, gravitational waves and fundamental physics: a roadmap
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Shadows and strong gravitational lensing: a brief review
• Gravitational Test Beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole
• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• Rotating black holes in $4D$ Einstein-Gauss-Bonnet gravity and its shadow
• The Shape of the Black Hole Photon Ring: A Precise Test of Strong-Field General Relativity
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Chaotic lensing around boson stars and Kerr black holes with scalar hair
• Testing General Relativity with the Shadow Size of Sgr A*
• A Quantitative Test of the No-Hair Theorem with Sgr A* using stars, pulsars, and the Event Horizon Telescope
• Imaging a boson star at the Galactic center
• How to tell an accreting boson star from a black hole
• Testing General Relativity with the Event Horizon Telescope
• Black Hole Shadow of Sgr A${}^{\ast }$ in Dark Matter Halo
• Rotating Black Hole Shadow in Perfect Fluid Dark Matter
• Sgr A* and General Relativity
• Asymptotic safety casts its shadow
• Constrained transport and adaptive mesh refinement in the Black Hole Accretion Code
• No-Hair Theorem in the Wake of Event Horizon Telescope
• Does the black hole shadow probe the event horizon geometry?
• The Scattering and Intrinsic Structure of Sagittarius A* at Radio Wavelengths
• Astrophysical imaging of Kerr black holes with scalar hair
• Testing the No-Hair Theorem with Observations of Black Holes in the Electromagnetic Spectrum
• Einstein-Æther Gravity in the light of Event Horizon Telescope Observations of M87*
• Persistent Asymmetric Structure of Sagittarius A* on Event Horizon Scales
• Observational signature of near-extremal Kerr-like black holes in a modified gravity theory at the Event Horizon Telescope
• Probing the magnetic field structure in Sgr A* on Black Hole Horizon Scales with Polarized Radiative Transfer Simulations
• Simulations of imaging the event horizon of Sagittarius A* from space
• Strong deflection gravitational lensing by a modified Hayward black hole
• Black Hole Shadow as a Test of General Relativity: Quadratic Gravity
• EHT tests of the strong-field regime of General Relativity
• Testing General Relativity with Accretion-Flow Imaging of Sgr A*
• Photon ring structure of rotating regular black holes and no-horizon spacetimes
• Strong field gravitational lensing by a charged Galileon black hole
• From a locality-principle for new physics to image features of regular spinning black holes with disks
• Superresolution Interferometric Imaging with Sparse Modeling Using Total Squared Variation --- Application to Imaging the Black Hole Shadow
• Measuring Spin from Relative Photon Ring Sizes
• TeraHertz Exploration and Zooming-in for Astrophysics (THEZA): ESA Voyage 2050 White Paper
• Testing the equivalence principle via the shadow of black holes
• A Parametric model for the shapes of black-hole shadows in non-Kerr spacetimes
• Metrics and Motivations for Earth-Space VLBI: Time-Resolving Sgr A* with the Event Horizon Telescope
• Black Hole Images as Tests of General Relativity: Effects of Plasma Physics
• Observational predictions of LQG motivated polymerized black holes and constraints from Sgr A* and M87*
• Separating Astrophysics and Geometry in Black Hole Images
• Spacetime Tomography Using The Event Horizon Telescope
• Fast-spinning black holes inferred from symmetrically limb-brightened radio jets
• Probing the Black Hole Metric. I. Black Hole Shadows and Binary Black-Hole Inspirals
• Selective Dynamical Imaging of Interferometric Data
• Lux in obscuro: Photon Orbits of Extremal Black Holes Revisited
• Deep Horizon; a machine learning network that recovers accreting black hole parameters
• The Galactic Center as a laboratory for theories of gravity and dark matter
• The Intrinsic Shape of Sagittarius A* at 3.5-mm Wavelength
• Black Hole Spin Signature in the Black Hole Shadow of M87 in the Flaring State
• Quantifying Intrinsic Variability of Sagittarius A* using Closure Phase Measurements of the Event Horizon Telescope
• Visibility of Black Hole Shadows in Low-luminosity AGN
• Black hole parameter estimation with synthetic Very Long Baseline Interferometry data from the ground and from space
• Testing General Relativity with the Black Hole Shadow Size and Asymmetry of Sagittarius A*: Limitations from Interstellar Scattering
• Testing General Relativity with X-ray reflection spectroscopy: The Konoplya-Rezzolla-Zhidenko parametrization
• Possibility of Identifying Matter around Rotating Black Hole with Black Hole Shadow
• Polarimetric signatures of the photon ring of a black hole that is pierced by a cosmic axion string
• GRay2: A General Purpose Geodesic Integrator for Kerr Spacetimes
• Numerical black hole initial data and shadows in dynamical Chern-Simons gravity
• Principal Component Analysis as a Tool for Characterizing Black Hole Images and Variability
• Relative depolarization of the black hole photon ring in GRMHD models of Sgr A* and M87*
• Ergosphere, photon region structure, and the shadow of a rotating charged Weyl black hole
• Polarization images of accretion flow around supermassive black holes: imprints of toroidal field structure
• Effects of modified gravity on the turnaround radius in cosmology
• Observing the Shadows of Stellar-Mass Black Holes with Binary Companions
• The Role of Adaptive Ray Tracing in Analyzing Black Hole Structure
• Lux in obscuro II: Photon Orbits of Extremal AdS Black Holes Revisited
• Can the Slow-Rotation Approximation be used in Electromagnetic Observations of Black Holes?
• Imaging black holes: past, present and future
• Electromagnetic vs. Lense-Thirring alignment of black hole accretion discs
• MeqSilhouette v2: Spectrally-resolved polarimetric synthetic data generation for the Event Horizon Telescope
• On-axis scattering of scalar fields by charged rotating black holes
• Killing horizons and surface gravities for a well-behaved three-function generalisation of the Kerr spacetime
• Micro-arcsecond structure of Sagittarius A* revealed by high-sensitivity 86 GHz VLBI observations
• RAIKOU: A General Relativistic, Multi-wavelength Radiative Transfer Code
• Principal-Component Interferometric Modeling (PRIMO), an Algorithm for EHT Data I: Reconstructing Images from Simulated EHT Observations
• STU Black Holes and SgrA*
• Time Domain Filtering of Resolved Images of Sgr A*
• Black holes, white holes, and near-horizon physics
• Black hole in a generalized Chaplygin-Jacobi dark fluid: shadow and light deflection angle
• Observational Signatures of Mass-Loading in Jets Launched by Rotating Black Holes
• Modified Kerr black holes surrounded by dark matter spike
• Approaching the black hole by numerical simulations
• Multiple Rings in the Shadow of Extremely Compact Objects
• Shadows of a generic class of spherically symmetric, static spacetimes
• Shadow analysis of an approximate rotating black hole solution with weakly coupled global monopole charge
• Observable strong field effects of extra spacetime dimension in the braneworld black hole
• GALLIFRAY -- A geometric modeling and parameter estimation framework for black hole images using bayesian techniques
• On the prospects of imaging Sagittarius A* from space
• Microlensing Black Hole Shadows
• The Nature of Black Hole Shadows
• Orbit design for mitigating interstellar scattering effects in Earth-space VLBI observations of Sgr A*