First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near the Event Horizon

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First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near the Event Horizon. / (EHT Collaboration).

In: Astrophysical Journal Letters, Vol. 910, No. 1, L13, 01.03.2021.

Research output: Contribution to journal › Article › peer-review

BibTeX

@article{da7644cb2e7f4c3da21752582fba93ac,

title = "First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near the Event Horizon",

abstract = "Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density n e ∼ 104-7 cm-3, magnetic field strength B ∼ 1-30 G, and electron temperature T e ∼ (1-12) 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3-20) 10-4 M o˙ yr-1.",

keywords = "Accretion, Black holes, Event horizons, Jets, Kerr black holes, Magnetic fields, Magnetohydrodynamics, Plasma astrophysics, Polarimetry, Radiative transfer, Radio jets, Relativistic jets, SAGITTARIUS-A-ASTERISK, ADVECTION-DOMINATED ACCRETION, RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS, SUPERMASSIVE BLACK-HOLE, GRMHD SIMULATIONS, FARADAY-ROTATION, CIRCULAR-POLARIZATION, PARTICLE-ACCELERATION, NONTHERMAL ELECTRONS, SYNCHROTRON EMISSION",

author = "{(EHT Collaboration)} and Kazunori Akiyama and Algaba, {Juan Carlos} and Antxon Alberdi and Walter Alef and Richard Anantua and Keiichi Asada and Rebecca Azulay and Baczko, {Anne Kathrin} and David Ball and Mislav Balokovi{\'c} and John Barrett and Benson, {Bradford A.} and Dan Bintley and Lindy Blackburn and Raymond Blundell and Wilfred Boland and Bouman, {Katherine L.} and Bower, {Geoffrey C.} and Hope Boyce and Michael Bremer and Brinkerink, {Christiaan D.} and Roger Brissenden and Silke Britzen and Broderick, {Avery E.} and Dominique Broguiere and Thomas Bronzwaer and Byun, {Do Young} and Carlstrom, {John E.} and Andrew Chael and Chan, {Chi Kwan} and Shami Chatterjee and Koushik Chatterjee and Chen, {Ming Tang} and Yongjun Chen and Chesler, {Paul M.} and Ilje Cho and Pierre Christian and Conway, {John E.} and Cordes, {James M.} and Crawford, {Thomas M.} and Crew, {Geoffrey B.} and Alejandro Cruz-Osorio and Yuzhu Cui and Jordy Davelaar and {De Laurentis}, Mariafelicia and Roger Deane and Jessica Dempsey and Gregory Desvignes and Jason Dexter and Svetlana Jorstad",

note = "Publisher Copyright: {\textcopyright} 2021. The Author(s). Published by the American Astronomical Society..",

year = "2021",

month = mar,

day = "1",

doi = "10.3847/2041-8213/abe4de",

language = "English",

volume = "910",

journal = "Astrophysical Journal Letters",

issn = "2041-8205",

publisher = "IOP Publishing Ltd.",

number = "1",

}

RIS

TY - JOUR

T1 - First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near the Event Horizon

AU - (EHT Collaboration)

AU - Akiyama, Kazunori

AU - Algaba, Juan Carlos

AU - Alberdi, Antxon

AU - Alef, Walter

AU - Anantua, Richard

AU - Asada, Keiichi

AU - Azulay, Rebecca

AU - Baczko, Anne Kathrin

AU - Ball, David

AU - Baloković, Mislav

AU - Barrett, John

AU - Benson, Bradford A.

AU - Bintley, Dan

AU - Blackburn, Lindy

AU - Blundell, Raymond

AU - Boland, Wilfred

AU - Bouman, Katherine L.

AU - Bower, Geoffrey C.

AU - Boyce, Hope

AU - Bremer, Michael

AU - Brinkerink, Christiaan D.

AU - Brissenden, Roger

AU - Britzen, Silke

AU - Broderick, Avery E.

AU - Broguiere, Dominique

AU - Bronzwaer, Thomas

AU - Byun, Do Young

AU - Carlstrom, John E.

AU - Chael, Andrew

AU - Chan, Chi Kwan

AU - Chatterjee, Shami

AU - Chatterjee, Koushik

AU - Chen, Ming Tang

AU - Chen, Yongjun

AU - Chesler, Paul M.

AU - Cho, Ilje

AU - Christian, Pierre

AU - Conway, John E.

AU - Cordes, James M.

AU - Crawford, Thomas M.

AU - Crew, Geoffrey B.

AU - Cruz-Osorio, Alejandro

AU - Cui, Yuzhu

AU - Davelaar, Jordy

AU - De Laurentis, Mariafelicia

AU - Deane, Roger

AU - Dempsey, Jessica

AU - Desvignes, Gregory

AU - Dexter, Jason

AU - Jorstad, Svetlana

PY - 2021/3/1

Y1 - 2021/3/1

N2 - Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density n e ∼ 104-7 cm-3, magnetic field strength B ∼ 1-30 G, and electron temperature T e ∼ (1-12) 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3-20) 10-4 M o˙ yr-1.

AB - Event Horizon Telescope (EHT) observations at 230 GHz have now imaged polarized emission around the supermassive black hole in M87 on event-horizon scales. This polarized synchrotron radiation probes the structure of magnetic fields and the plasma properties near the black hole. Here we compare the resolved polarization structure observed by the EHT, along with simultaneous unresolved observations with the Atacama Large Millimeter/submillimeter Array, to expectations from theoretical models. The low fractional linear polarization in the resolved image suggests that the polarization is scrambled on scales smaller than the EHT beam, which we attribute to Faraday rotation internal to the emission region. We estimate the average density n e ∼ 104-7 cm-3, magnetic field strength B ∼ 1-30 G, and electron temperature T e ∼ (1-12) 1010 K of the radiating plasma in a simple one-zone emission model. We show that the net azimuthal linear polarization pattern may result from organized, poloidal magnetic fields in the emission region. In a quantitative comparison with a large library of simulated polarimetric images from general relativistic magnetohydrodynamic (GRMHD) simulations, we identify a subset of physical models that can explain critical features of the polarimetric EHT observations while producing a relativistic jet of sufficient power. The consistent GRMHD models are all of magnetically arrested accretion disks, where near-horizon magnetic fields are dynamically important. We use the models to infer a mass accretion rate onto the black hole in M87 of (3-20) 10-4 M o˙ yr-1.

KW - Accretion

KW - Black holes

KW - Event horizons

KW - Jets

KW - Kerr black holes

KW - Magnetic fields

KW - Magnetohydrodynamics

KW - Plasma astrophysics

KW - Polarimetry

KW - Radiative transfer

KW - Radio jets

KW - Relativistic jets

KW - SAGITTARIUS-A-ASTERISK

KW - ADVECTION-DOMINATED ACCRETION

KW - RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS

KW - SUPERMASSIVE BLACK-HOLE

KW - GRMHD SIMULATIONS

KW - FARADAY-ROTATION

KW - CIRCULAR-POLARIZATION

KW - PARTICLE-ACCELERATION

KW - NONTHERMAL ELECTRONS

KW - SYNCHROTRON EMISSION

UR - http://www.scopus.com/inward/record.url?scp=85103626755&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/95363e76-b4f7-32af-86fd-4b116e169030/

U2 - 10.3847/2041-8213/abe4de

DO - 10.3847/2041-8213/abe4de

M3 - Article

AN - SCOPUS:85103626755

VL - 910

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 1

M1 - L13

ER -

ID: 86458636