The Polarized Image of a Synchrotron Emitting Ring of Gas Orbiting a Black Hole

Abstract

Synchrotron radiation from hot gas near a black hole results in a polarized image. The image polarization is determined by effects including the orientation of the magnetic field in the emitting region, relativistic motion of the gas, strong gravitational lensing by the black hole, and parallel transport in the curved spacetime. We explore these effects using a simple model of an axisymmetric, equatorial accretion disk around a Schwarzschild black hole. By using an approximate expression for the null geodesics derived by Beloborodov (2002) and conservation of the Walker-Penrose constant, we provide analytic estimates for the image polarization. We test this model using currently favored general relativistic magnetohydrodynamic simulations of M87*, using ring parameters given by the simulations. For a subset of these with modest Faraday effects, we show that the ring model broadly reproduces the polarimetric image morphology. Our model also predicts the polarization evolution for compact flaring regions, such as those observed from Sgr A* with GRAVITY. With suitably chosen parameters, our simple model can reproduce the EVPA pattern and relative polarized intensity in Event Horizon Telescope images of M87*. Under the physically motivated assumption that the magnetic field trails the fluid velocity, this comparison is consistent with the clockwise rotation inferred from total intensity images.

arXiv comment29 pages, 11 figures, published in ApJ on May 3

References in corpus (42)

• 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
• Efficient Generation of Jets from Magnetically Arrested Accretion on a Rapidly Spinning Black Hole
• First M87 Event Horizon Telescope Results. II. Array and Instrumentation
• Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
• First M87 Event Horizon Telescope Results. III. Data Processing and Calibration
• Magnetically Arrested Disk: An Energetically Efficient Accretion Flow
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• Three-dimensional MHD Simulations of Radiatively Inefficient Accretion Flows
• First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
• Multi-Temperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations
• Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA*
• The Structure and Dynamics of the Sub-parsec Scale Jet in M87 Based on 50 VLBA Observations Over 17 Years at 43 GHz
• General relativistic magnetohydrodynamical simulations of the jet in M87
• Gravitational Bending of Light Near Compact Objects
• Imaging Optically-Thin Hot Spots Near the Black Hole Horizon of Sgr A* at Radio and Near-Infrared Wavelengths
• Lensing by Kerr Black Holes
• Resolved Magnetic-Field Structure and Variability Near the Event Horizon of Sagittarius A*
• X-ray Polarization from Accreting Black Holes: II. The Thermal State
• Polarimetry of near-infrared flares from Sagittarius A*
• Imaging Bright Spots in the Accretion Flow Near the Black Hole Horizon of Sgr A*
• Sagittarius A* Accretion Flow and Black Hole Parameters from General Relativistic Dynamical and Polarized Radiative Modeling
• The Null Geodesics of the Kerr Exterior
• Harmony in Electrons: Cyclotron and Synchrotron Emission by Thermal Electrons in a Magnetic Field
• Universal Polarimetric Signatures of the Black Hole Photon Ring
• A polarised infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots
• Inferring the Inclination of a Black Hole Accretion Disk from Observations of its Polarized Continuum Radiation
• Polarimetric Imaging of the Massive Black Hole at the Galactic Center
• Faraday rotation in GRMHD simulations of the jet launching zone of M87
• ALMA Polarimetry of Sgr A*: Probing the Accretion Flow from the Event Horizon to the Bondi Radius
• Probing the magnetic field structure in Sgr A* on Black Hole Horizon Scales with Polarized Radiative Transfer Simulations
• Discriminating Accretion States via Rotational Symmetry in Simulated Polarimetric Images of M87
• The Submillimeter Polarization of Sgr A*
• Dynamically important magnetic fields near the event horizon of Sgr A*
• Near infrared flares of Sagittarius A*: Importance of near infrared polarimetry
• The impact of Faraday effects on polarized black hole images of Sagittarius A*
• Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI
• Decomposing the Internal Faraday Rotation of Black Hole Accretion Flows
• Predicting the X-ray polarization of type-2 Seyfert galaxies
• Maximum Observable Blueshift from Circular Equatorial Kerr Orbiters

Cited by in corpus (46)

• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• Polarimetry and Astrometry of NIR Flares as Event Horizon Scale, Dynamical Probes for the Mass of Sgr A*
• Axion-plasmon or magnetized plasma effect on an observable shadow and gravitational lensing of a Schwarzschild black hole
• Polarized Image of Equatorial Emission in the Kerr Geometry
• Polarized image of a Schwarzschild black hole with a thin accretion disk as photon couples to Weyl tensor
• Adaptive Analytical Ray Tracing of Black Hole Photon Rings
• Polarized image of a rotating black hole in Scalar-Tensor-Vector-Gravity theory
• Black Hole Polarimetry I: A Signature of Electromagnetic Energy Extraction
• Charged black-bounce spacetimes: Photon rings, shadows and observational appearances
• Polarimetric signatures of hot spots in black hole accretion flows
• Analytical techniques for polarimetric imaging of accretion flows in Schwarzschild metric
• Unraveling Twisty Linear Polarization Morphologies in Black Hole Images
• Shadow of black hole surrounded by magnetized plasma: Axion-plasmon cloud
• Image of Bonnor black dihole with a thin accretion disk and its polarization information
• Circular orbits and polarized images of charged particles orbiting Kerr black hole with a weak magnetic field
• Bayesian Accretion Modeling: Axisymmetric Equatorial Emission in the Kerr Spacetime
• Polarized Images of Synchrotron Radiations in Curved Spacetime
• Image of the Schwarzschild black hole pierced by a cosmic string with a thin accretion disk
• Signatures of Black Hole Spin and Plasma Acceleration in Jet Polarimetry
• How Spatially Resolved Polarimetry Informs Black Hole Accretion Flow Models
• Study of general relativistic magnetohydrodynamic accretion flow around black holes
• Relativistic Signatures of Flux Eruption Events Near Black Holes
• Analytical expressions for pulse profile of neutron stars in plasma environments
• Particle dynamics and the accretion disk around a Self-dual Black Hole immersed in a magnetic field in Loop Quantum Gravity
• Bayesian Black Hole Photogrammetry
• Polarization Observations of AGN Jets: Past and Future
• Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes
• Multi-Frequency Models of Black Hole Photon Rings from Low-Luminosity Accretion Disks
• Energy Extraction from Loop Quantum Black Holes: The Role of Magnetic Penrose Process and Quantum Gravity Effects with Astrophysical Insights
• Observational Signatures of Black Hole Accretion: Rotating vs. Spherical Flows with Tilted Magnetic Fields
• Astrophysical insights into magnetic Penrose process around parameterized Konoplya-Rezzolla-Zhidenko black hole
• Electromagnetic signatures of strong-field gravity from accreting black holes
• Accurate analytical modeling of light rays in spherically symmetric spacetimes: Applications in the study of black hole accretion disks and polarimetry
• Semi-analytic studies of accretion disk and magnetic field geometry in M87*
• Did the Event Horizon Telescope Detect the Base of the Sub-Milliarsecond Tubular Jet in M\,87?
• Optical images of the Kerr-Sen black hole and thin accretion disk
• Probing Observable Features of Lorentz violation in Low-Energy Hořava Gravity with Accretion Disk Images of Black Hole
• Effect of nonlinear electrodynamics on polarization distribution around black hole
• Assessing the Role of Intrinsic Variability in Black Hole Parameter Inference using Multi-Epoch EHT Data
• Characterization of black hole accretion through image moment invariants
• Thin accretion disk around Schwarzschild-like black hole in bumblebee gravity
• Polarization Signatures of Rotating Black Holes in Perfect Fluid Dark Matter Spacetimes
• Polarization Signatures of Inspiraling Hotspots around Kerr Black Holes
• Fast and accurate analytical formulas for light propagation in general static, spherically symmetric spacetimes
• Photon Ring Symmetries in Simulated Linear Polarization Images of Messier 87*
• Polarization Signatures of Magnetic Reconnection Bubbles near Black Holes