Hybrid Very Long Baseline Interferometry Imaging and Modeling with Themis

Abstract

Generating images from very long baseline interferometric observations poses a difficult, and generally not unique, inversion problem. This problem is simplified by the introduction of constraints, some generic (e.g., positivity of the intensity) and others motivated by physical considerations (e.g., smoothness, instrument resolution). It is further complicated by the need to simultaneously address instrumental systematic uncertainties and sparse coverage in the u-v plane. We report a new Bayesian image reconstruction technique in the parameter estimation framework Themis that has been developed for the Event Horizon Telescope. This has two key features: first, the full Bayesian treatment of the image reconstruction makes it possible to generate a full posterior for the images, permitting a rigorous and quantitative investigation into the statistical significance of image features. Second, it is possible to seamlessly incorporate directly modeled features simultaneously with image reconstruction. We demonstrate this second capability by incorporating a narrow, slashed ring in reconstructions of simulated M87 data in an attempt to detect and characterize the photon ring. We show that it is possible to obtain high-fidelity photon ring sizes, enabling mass measurements with accuracies of 2%-5% that are essentially insensitive to astrophysical uncertainties, and creating opportunities for precision tests of general relativity.

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Cited by in corpus (33)

• First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
• 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
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Key Science Goals for the Next-Generation Event Horizon Telescope
• Photon rings of spherically symmetric black holes and robust tests of non-Kerr metrics
• First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
• From a locality-principle for new physics to image features of regular spinning black holes with disks
• The Photon Ring in M87*
• Measuring Spin from Relative Photon Ring Sizes
• Resolving the inner parsec of the blazar J1924-2914 with the Event Horizon Telescope
• Universal signatures of singularity-resolving physics in photon rings of black holes and horizonless objects
• Optical appearance of black holes surrounded by a dark matter halo
• How narrow is the M87* ring? II. A new geometric model
• Black hole parameter estimation with synthetic Very Long Baseline Interferometry data from the ground and from space
• The Event Horizon Telescope Image of the Quasar NRAO 530
• Variational Image Feature Extraction for the Event Horizon Telescope
• A D-term Modeling Code (DMC) for simultaneous calibration and full-Stokes imaging of very long baseline interferometric data
• Horizonless spacetimes as seen by present and next-generation Event Horizon Telescope arrays
• Using multiobjective optimization to reconstruct interferometric data (I)
• A Lensing-Band Approach to Spacetime Constraints
• Multi-scale and Multi-directional VLBI Imaging with CLEAN
• alpha-Deep Probabilistic Inference (alpha-DPI): efficient uncertainty quantification from exoplanet astrometry to black hole feature extraction
• Deep Probabilistic Imaging: Uncertainty Quantification and Multi-modal Solution Characterization for Computational Imaging
• Dynamic and polarimetric VLBI imaging with a multiscalar approach
• Time-dependent visibility modelling of a relativistic jet in the X-ray binary MAXI J1803-298
• Measuring the Ellipticity of M 87* Images
• Relativistic Signatures of Flux Eruption Events Near Black Holes
• Swarm intelligence for full Stokes dynamic imaging reconstruction of interferometric data
• Prospects of using closure traces directly for imaging in Very Long Baseline Interferometry
• Origin of the ring ellipticity in the black hole images of M87*
• New Views of Black Holes from Computational Imaging
• Very-Long Baseline Interferometry Imaging with Closure Invariants using Conditional Image Diffusion