Black Hole Magnetic Fields and Their Imprint on Circular Polarization Images

Abstract

The circular polarization of black hole accretion flows can encode properties of the underlying magnetic field structure. Using general relativistic magnetohydrodynamics (GRMHD) simulations, we study the imprint of magnetic field geometry on circular polarization images potentially observable by the Event Horizon Telescope (EHT). We decompose images into the different mechanisms that generate circular polarization in these models, which are sensitive to both the line of sight direction and twist of the magnetic field. In these models, a stable sign of the circular polarization over time, as observed for several sources, can be attributed to a stability of these properties. We illustrate how different aspects of a generic helical magnetic field geometry become imprinted on a circular polarization image. We also identify novel effects of light bending that affect the circular polarization image on event horizon scales. One consequence is the sign flipping of successive photon rings in face-on systems, which if observable and uncorrupted by Faraday rotation, can directly encode the handedness of the approaching magnetic field.

20 pages, 19 figures, in review with MNRAS

References in corpus (18)

• 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
• 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 M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
• The Influence of Magnetic Field Geometry on the Evolution of Black Hole Accretion Flows: Similar Disks, Drastically Different Jets
• Polarimetric properties of Event Horizon Telescope targets from ALMA
• Discriminating Accretion States via Rotational Symmetry in Simulated Polarimetric Images of M87
• Radio Circular Polarization Produced in Helical Magnetic Fields in Eight Active Galactic Nuclei
• Probing the Parsec-scale Accretion Flow of 3C 84 with Millimeter Polarimetry
• Decomposing the Internal Faraday Rotation of Black Hole Accretion Flows
• Unraveling circular polarimetric images of magnetically arrested accretion flows near event horizon of a black hole
• Accretion disk radiation dynamics and the cosmic battery
• Numerical simulations of the Cosmic Battery in accretion flows around astrophysical black holes
• Constraining Radiatively Inefficient Accretion Flows with Polarization

Cited by in corpus (26)

• First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
• Polarized Image of Equatorial Emission in the Kerr Geometry
• Unraveling Twisty Linear Polarization Morphologies in Black Hole Images
• Using Machine Learning to Link Black Hole Accretion Flows with Spatially Resolved Polarimetric Observables
• Circular orbits and polarized images of charged particles orbiting Kerr black hole with a weak magnetic field
• Polarized Images of Synchrotron Radiations in Curved Spacetime
• Probing Axions via Light Circular Polarization and Event Horizon Telescope
• How Spatially Resolved Polarimetry Informs Black Hole Accretion Flow Models
• Probing Plasma Physics with Spectral Index Maps of Accreting Black Holes on Event Horizon Scales
• Polarization Observations of AGN Jets: Past and Future
• Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes
• Survey of Non-thermal Electron around Supermassive Black Holes through Polarization Flips
• Electromagnetic signatures of strong-field gravity from accreting black holes
• Photon ring polarimetry with next-generation black hole imaging I. M87*
• Deep learning inference with the Event Horizon Telescope III. Zingularity results from the 2017 observations and predictions for future array expansions
• KHARMA: Flexible, Portable Performance for GRMHD
• Jet Archaeology and Forecasting: Image Variability and Magnetic Field Configuration
• Diverse Polarimetric Features of AGN Jets from Various Viewing Angles: Towards a Unified View
• On the Non-Minimal Coupling of Magnetic Fields with Gravity in Schwarzschild Spacetime
• Characterization of black hole accretion through image moment invariants
• Polarization Signatures of Rotating Black Holes in Perfect Fluid Dark Matter Spacetimes
• Probing the magneto-ionic medium of the Milky Way using pulsars
• Photon Ring Symmetries in Simulated Linear Polarization Images of Messier 87*
• PATOKA: Simulating Electromagnetic Observables of Black Hole Accretion
• From electrons to Janskys: Full stokes polarized radiative transfer in 3D relativistic particle-in-cell jet simulations
• Investigating the Disk-Jet Structure in M87 through Flux Separation in the Linear and Circular Polarization Images