Spacetime Tomography Using The Event Horizon Telescope

Abstract

We have now entered the new era of high-resolution imaging astronomy with the beginning of the Event Horizon Telescope (EHT). The EHT can resolve the dynamics of matter in the immediate vicinity around black holes at and below the horizon scale. One of the candidate black holes, Sagittarius A* flares 1\-4 times a day depending on the wavelength. A possible interpretation of these flares could be hotspots generated through magnetic reconnection events in the accretion flow. In this paper, we construct a semi-analytical model for hotspots that include the effects of shearing as a spot moves along the accretion flow. We then explore the ability of the EHT to recover these hotspots. Even including significant systematic uncertainties, such as thermal noise, diffractive scattering, and background emission due to an accretion disk, we were able to recover the hotspots and spacetime structure to sub-percent precision. Moreover, by observing multiple flaring events we show how the EHT could be used to tomographically map spacetime. This provides new avenues for testing relativistic fluid dynamics and general relativity near the event horizon of supermassive black holes.

Accepted to ApJ (17 pages, 15 figures) (revised edition corrected some affiliations)

References in corpus (19)

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Cited by in corpus (22)

• Key Science Goals for the Next-Generation Event Horizon Telescope
• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• Polarized Image of Equatorial Emission in the Kerr Geometry
• Photon Ring Autocorrelations
• Dynamically important magnetic fields near the event horizon of Sgr A*
• Measuring Spin from Relative Photon Ring Sizes
• Image features of spinning regular black holes based on a locality principle
• Universal signatures of singularity-resolving physics in photon rings of black holes and horizonless objects
• Polarimetric signatures of hot spots in black hole accretion flows
• Fitting the light curves of Sagittarius A* with a hot-spot model
• Bayesian Accretion Modeling: Axisymmetric Equatorial Emission in the Kerr Spacetime
• Accretion Flow Morphology in Numerical Simulations of Black Holes from the ngEHT Model Library: The Impact of Radiation Physics
• Light echos and coherent autocorrelations in a black hole spacetime
• A Lensing-Band Approach to Spacetime Constraints
• Hot-spots around Sagittarius A*: Joint fits to astrometry and polarimetry
• Dynamic and polarimetric VLBI imaging with a multiscalar approach
• Extreme lensing induces spectro-temporal correlations in black-hole signals
• Swarm intelligence for full Stokes dynamic imaging reconstruction of interferometric data
• Polarized signatures of adiabatically expanding hotspots in Sgr A*'s accretion flow
• Forward Ray Tracing and Hot Spots in Kerr Spacetime
• Inferring Black Hole Spin from Interferometric Measurements of the First Photon Ring: A Geometric Approach
• Semi-analytic studies of accretion disk and magnetic field geometry in M87*