Bayesian Black Hole Photogrammetry

Abstract

We propose a simple, analytic dual-cone accretion model for horizon scale images of the cores of Low-Luminosity Active Galactic Nuclei (LLAGN), including those observed by the Event Horizon Telescope (EHT). Our underlying model is of synchrotron emission from an axisymmetric, magnetized plasma, which is constrained to flow within two oppositely oriented cones that are aligned with the black hole's spin axis. We show that this model can accurately reproduce images for a variety of time-averaged general relativistic magnetohydrodynamic (GRMHD) simulations, that it accurately recovers both the black hole and emission parameters from these simulations, and that it is sufficiently efficient to be used to measure these parameters in a Bayesian inference framework with radio interferometric data. We show that non-trivial topologies in the source image can result in non-trivial multi-modal solutions when applied to observations from a sparse array, such as the EHT 2017 observations of M87${}^{\ast }$. The presence of these degeneracies underscores the importance of employing Bayesian techniques that adequately sample the posterior space for the interpretation of EHT measurements. We fit our model to the EHT observations of M87${}^{\ast }$ and find a 95% Highest Posterior Density Interval (HPDI) for the mass-to-distance ratio of ${\theta }_g\in (2.84,3.75)\mu \mathrm{as}$, and give an inclination of ${\theta }_{\mathrm{o}}\in (11^{\circ },24^{\circ })$. These new measurements are consistent with mass measurements from the EHT and stellar dynamical estimates (e.g., Gebhardt et al. 2011; EHTC et al. 2019a,b; Liepold et al. 2023), and with the spin axis inclination inferred from properties of the M87${}^{\ast }$ jet (e.g., Walker et al. 2018).

References in corpus (24)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• 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
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• Black Hole Shadows, Photon Rings, and Lensing Rings
• 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. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• Kinematics of the jet in M87 on scales of 100 -- 1000 Schwarzschild radii
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Precessing jet nozzle connecting to a spinning black hole in M87
• First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
• Discriminating Accretion States via Rotational Symmetry in Simulated Polarimetric Images of M87
• The Effects of Accretion Flow Dynamics on the Black Hole Shadow of Sagittarius A${}^{\ast }$
• Keck Integral-Field Spectroscopy of M87 Reveals an Intrinsically Triaxial Galaxy and a Revised Black Hole Mass
• How narrow is the M87* ring? II. A new geometric model
• Bayesian Accretion Modeling: Axisymmetric Equatorial Emission in the Kerr Spacetime
• Photon Emission from Circular Equatorial Kerr Orbiters
• Jets and Rings in Images of Spinning Black Holes

Cited by in corpus (4)

• Multi-Frequency Models of Black Hole Photon Rings from Low-Luminosity Accretion Disks
• Observational properties of black hole in quantum fluctuation modified gravity
• Assessing the Role of Intrinsic Variability in Black Hole Parameter Inference using Multi-Epoch EHT Data
• Observational distinguishability of the Kerr and Kerr-Hayward metrics to EHT