Polarimetric properties of Event Horizon Telescope targets from ALMA

Abstract

We present the results from a full polarization study carried out with ALMA during the first VLBI campaign, which was conducted in Apr 2017 in the $\lambda$3mm and $\lambda$1.3mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud AGN. We detect high linear polarization fractions (2-15%) and large rotation measures (RM $>10^{3.3}-10^{5.5}$ rad m${}^{-2}$). For Sgr A* we report a mean RM of $(-4.2\pm 0.3)\times 10^5$ rad m${}^{-2}$ at 1.3 mm, consistent with measurements over the past decade, and, for the first time, an RM of $(-2.1\pm 0.1)\times 10^5$ rad m${}^{-2}$ at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at mm wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year time-scale, spanning the range from -1.2 to 0.3 $\times 10^5$ rad m${}^{-2}$ at 3 mm and -4.1 to 1.5 $\times 10^5$ rad m${}^{-2}$ at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT and ALMA. These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA.

62 pages, 26 figures, published in The Astrophysical Journal Letters on March 24, 2021

References in corpus (37)

• 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
• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• 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
• Jet Launching Structure Resolved Near the Supermassive Black Hole in M87
• A massive binary black-hole system in OJ287 and a test of general relativity
• An Unambiguous Detection of Faraday Rotation in Sagittarius A*
• Dynamics of Ionized Gas at the Galactic Center: VLA Observations of the 3D Velocity Field and Location of the Ionized Streams in Sagittarius A West
• MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments. XI. Spectral distributions
• The Size, Shape, and Scattering of Sagittarius A* at 86 GHz: First VLBI with ALMA
• Faraday rotation and polarization gradients in the jet of 3C~120: Interaction with the external medium and a helical magnetic field?
• Black-hole jets without large-scale net magnetic flux
• Faraday rotation in the jet of M87 inside the Bondi radius: indication of winds from hot accretion flows confining the relativistic jet
• The Rotation Measure and 3.5mm Polarization of Sgr A*
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. III. Characterisation of total flux density and polarisation variability of relativistic jets
• The ALMA Phasing System: A Beamforming Capability for Ultra-High-Resolution Science at (Sub)Millimeter Wavelengths
• Are Spine--Sheath Polarization Structures in the Jets of Active Galactic Nuclei Associated with Helical Magnetic Fields?
• Calibration of ALMA as a phased array: ALMA observations during the 2017 VLBI campaign
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. II. Widespread circular polarisation
• Probing the Parsec-scale Accretion Flow of 3C 84 with Millimeter Polarimetry
• Decomposing the Internal Faraday Rotation of Black Hole Accretion Flows
• Disentangling the Circumnuclear Environs of Centaurus A: III. An Inner Molecular Ring, Nuclear Shocks and the CO to warm H2 interface
• Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm
• Enhanced Polarized Emission from the One-Parsec-Scale Hotspot of 3C 84 as a Result of the Interaction with Clumpy Ambient Medium
• Parsec Scale Faraday-Rotation Structure Across the Jets of 9 Active Galactic Nuclei
• The 15--43-GHz Parsec-scale Circular Polarization of 41 Active Galactic Nuclei
• An accretion-jet model for M87: interpreting the spectral energy distribution and Faraday rotation measure
• Characterizing the accuracy of ALMA linear-polarization mosaics
• A Compact Jet at the Infrared Heart of the Prototypical Low-Luminosity AGN in NGC 1052
• ALMA Observations of the Physical and Chemical Conditions in Centaurus A
• First M87 Event Horizon Telescope Results and the Role of ALMA
• What is the Hidden Depolarization Mechanism in Low Luminosity AGN?

Cited by in corpus (72)

• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• 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. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• A ring-like accretion structure in M87 connecting its black hole and jet
• Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
• Millimeter light curves of Sagittarius A* observed during the 2017 Event Horizon Telescope campaign
• Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
• Magnetic reconnection and plasmoid formation in three-dimensional accretion flows around black holes
• Resolving the inner parsec of the blazar J1924-2914 with the Event Horizon Telescope
• The Accretion flow in M87 is really MAD
• Black Hole Magnetic Fields and Their Imprint on Circular Polarization Images
• Unraveling circular polarimetric images of magnetically arrested accretion flows near event horizon of a black hole
• X-ray spectral components of the blazar and binary black hole candidate OJ 287 (2005-2020)
• Polarimetric signatures of hot spots in black hole accretion flows
• Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode
• Unraveling Twisty Linear Polarization Morphologies in Black Hole Images
• Using Machine Learning to Link Black Hole Accretion Flows with Spatially Resolved Polarimetric Observables
• Unravelling the Innermost Jet Structure of OJ 287 with the First GMVA+ALMA Observations
• The Event Horizon Telescope Image of the Quasar NRAO 530
• Positron Effects on Polarized Images and Spectra from Jet and Accretion Flow Models of M87* and Sgr A*
• MOMO VI: Multifrequency radio variability of the blazar OJ 287 from 2015-2022, absence of predicted 2021 precursor-flare activity, and a new binary interpretation of the 2016/2017 outburst
• Ordered magnetic fields around the 3C 84 central black hole
• The internal Faraday screen of Sagittarius A*
• Limits on X-ray Polarization at the Core of Centaurus A as Observed with the Imaging X-ray Polarimetry Explorer
• Metric-affine gravity effects on terrestrial (exo-)planets profiles
• MOMO IV: The complete Swift X-ray and UV/optical light curve and characteristic variability of the blazar OJ 287 during the last two decades
• M87: a cosmic laboratory for deciphering black hole accretion and jet formation
• Detecting Axion Dark Matter with Black Hole Polarimetry
• Compact jets dominate the continuum emission in low-luminosity active galactic nuclei
• Jupiter and jovian (exo)-planets in Palatini $f(\bar{R})$ gravity
• Black Holes Up Close
• A Characterization of the ALMA Phasing System at 345 GHz
• Probing Axions via Light Circular Polarization and Event Horizon Telescope
• How Spatially Resolved Polarimetry Informs Black Hole Accretion Flow Models
• Study of general relativistic magnetohydrodynamic accretion flow around black holes
• Probing Plasma Physics with Spectral Index Maps of Accreting Black Holes on Event Horizon Scales
• Testing the linear relationship between black hole mass and variability timescale in low-luminosity AGN at submillimeter wavelengths
• Giant planet formation in Palatini gravity
• A multi-frequency study of sub-parsec jets with the Event Horizon Telescope
• A first search of transients in the Galactic Center from 230 GHz ALMA observations
• Polarimetric Geometric Modeling for mm-VLBI Observations of Black Holes
• Non-homogeneous exoplanets in metric-affine gravity
• cuHARM : a new GPU accelerated GR-MHD code and its application to ADAF disks
• Chaotic magnetic disconnections trigger flux eruptions in accretion flows channeled onto magnetically saturated Kerr black holes
• The putative center in NGC 1052
• 3D PIC Simulations for Relativistic Jets with a Toroidal Magnetic Field
• Polarized signatures of adiabatically expanding hotspots in Sgr A*'s accretion flow
• Electromagnetic signatures of strong-field gravity from accreting black holes
• First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA
• 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
• Semi-analytic studies of accretion disk and magnetic field geometry in M87*
• Deep learning inference with the Event Horizon Telescope II. The Zingularity framework for Bayesian artificial neural networks
• ALMA polarimetry of radio-quiet AGNs
• Robust analysis of differential Faraday Rotation based on interferometric closure observables
• Diverse Polarimetric Features of AGN Jets from Various Viewing Angles: Towards a Unified View
• Kilogauss magnetic field and jet dynamics in the quasar NRAO 530
• The Bardeen-Petterson Effect as an Observable Support for the Blanford-Payne Process Black Hole Jet Production
• Spatially resolved spectral properties of M87* on event horizon scales
• Full-polarization millimeter wavelength variability of Sagittarius A* during the 2018 EHT campaign
• A revised view of the linear polarization in the subparsec core of M87 at 7 mm
• Orbit design for mitigating interstellar scattering effects in Earth-space VLBI observations of Sgr A*
• Investigating the Disk-Jet Structure in M87 through Flux Separation in the Linear and Circular Polarization Images
• The science case and challenges of space-borne sub-millimeter interferometry
• Constraints on magnetic field and particle content in blazar jets through optical circular polarization
• Ergomagnetosphere, Ejection Disc, Magnetopause in M87. I Global Flow of Mass, Angular Momentum, Energy and Current