The Black Hole Explorer: Photon Ring Science, Detection and Shape Measurement

Abstract

General relativity predicts that black hole images ought to display a bright, thin (and as-of-yet-unresolved) ring. This "photon ring" is produced by photons that explore the strong gravity of the black hole, flowing along trajectories that experience extreme light bending within a few Schwarzschild radii of the horizon before escaping. The shape of the photon ring is largely insensitive to the precise details of the emission from the astronomical source surrounding the black hole and therefore provides a direct probe of the Kerr geometry and its parameters. The Black Hole Explorer (BHEX) is a proposed space-based experiment targeting the supermassive black holes M87* and Sgr A* with radio-interferometric observations at frequencies of 100 GHz through 300 GHz and from an orbital distance of ~30,000 km. This design will enable measurements of the photon rings around both M87* and Sgr A*, confirming the Kerr nature of these sources and delivering sharp estimates of their masses and spins.

Submitted to SPIE Space Telescopes & Instrumentation

References in corpus (14)

• 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. V. Physical Origin of the Asymmetric Ring
• Black Hole Shadows, Photon Rings, and Lensing Rings
• The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits
• The Shadow of a Spherically Accreting Black Hole
• Lensing by Kerr Black Holes
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
• Images and photon ring signatures of thick disks around black holes
• Stochastic Optics: A Scattering Mitigation Framework for Radio Interferometric Imaging
• Measuring the shape of a black hole photon ring
• Demonstrating Photon Ring Existence with Single-Baseline Polarimetry
• Bayesian Accretion Modeling: Axisymmetric Equatorial Emission in the Kerr Spacetime
• Disks as Inhomogeneous, Anisotropic Gaussian Random Fields

Cited by in corpus (5)

• Multi-Frequency Models of Black Hole Photon Rings from Low-Luminosity Accretion Disks
• The Black Hole Explorer: Using the Photon Ring to Visualize Spacetime Around the Black Hole
• The Japanese Vision for the Black Hole Explorer Mission
• A General Discussion on Photon Spheres in Different Categories of Spacetimes
• Limiting the Yukawa Gravity through the Black Hole Shadows of Sgr A* and M87*