eprintid: 10190893
rev_number: 10
eprint_status: archive
userid: 699
dir: disk0/10/19/08/93
datestamp: 2024-04-18 09:51:39
lastmod: 2024-04-18 10:05:11
status_changed: 2024-04-18 10:05:11
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Akiyama, K
creators_name: Alberdi, A
creators_name: Alef, W
creators_name: Algaba, JC
creators_name: Anantua, R
creators_name: Asada, K
creators_name: Azulay, R
creators_name: Bach, U
creators_name: Baczko, AK
creators_name: Ball, D
creators_name: Baloković, M
creators_name: Bandyopadhyay, B
creators_name: Barrett, J
creators_name: Bauböck, M
creators_name: Benson, BA
creators_name: Bintley, D
creators_name: Blackburn, L
creators_name: Blundell, R
creators_name: Bouman, KL
creators_name: Bower, GC
creators_name: Boyce, H
creators_name: Bremer, M
creators_name: Brinkerink, CD
creators_name: Brissenden, R
creators_name: Britzen, S
creators_name: Broderick, AE
creators_name: Broguiere, D
creators_name: Bronzwaer, T
creators_name: Bustamante, S
creators_name: Byun, DY
creators_name: Carlstrom, JE
creators_name: Ceccobello, C
creators_name: Chael, A
creators_name: Chan, CK
creators_name: Chang, DO
creators_name: Chatterjee, K
creators_name: Chatterjee, S
creators_name: Chen, MT
creators_name: Chen, Y
creators_name: Cheng, X
creators_name: Cho, I
creators_name: Christian, P
creators_name: Conroy, NS
creators_name: Conway, JE
creators_name: Cordes, JM
creators_name: Crawford, TM
creators_name: Crew, GB
creators_name: Cruz-Osorio, A
creators_name: Cui, Y
creators_name: Dahale, R
creators_name: Davelaar, J
creators_name: De Laurentis, M
creators_name: Deane, R
creators_name: Dempsey, J
creators_name: Desvignes, G
creators_name: Dexter, J
creators_name: Dhruv, V
creators_name: Dihingia, IK
creators_name: Doeleman, SS
creators_name: Dougall, S
creators_name: Dzib, SA
creators_name: Eatough, RP
creators_name: Emami, R
creators_name: Falcke, H
creators_name: Farah, J
creators_name: Fish, VL
creators_name: Fomalont, E
creators_name: Ford, HA
creators_name: Foschi, M
creators_name: Fraga-Encinas, R
creators_name: Freeman, WT
creators_name: Friberg, P
creators_name: Fromm, CM
creators_name: Fuentes, A
creators_name: Galison, P
creators_name: Gammie, CF
creators_name: García, R
creators_name: Gentaz, O
creators_name: Georgiev, B
creators_name: Goddi, C
creators_name: Gold, R
creators_name: Gómez-Ruiz, AI
creators_name: Gómez, JL
creators_name: Gu, M
creators_name: Gurwell, M
creators_name: Hada, K
creators_name: Haggard, D
creators_name: Haworth, K
creators_name: Hecht, MH
creators_name: Hesper, R
creators_name: Heumann, D
creators_name: Ho, LC
creators_name: Ho, P
creators_name: Honma, M
creators_name: Huang, CWL
creators_name: Huang, L
creators_name: Hughes, DH
creators_name: Ikeda, S
creators_name: Violette Impellizzeri, CM
creators_name: Inoue, M
title: First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring
ispublished: pub
divisions: UCL
divisions: B04
divisions: C06
divisions: F63
note: Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence, https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
abstract: In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A* (equivalent to ≈46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow.
date: 2024-04-01
date_type: published
publisher: American Astronomical Society
official_url: http://dx.doi.org/10.3847/2041-8213/ad2df1
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2268362
doi: 10.3847/2041-8213/ad2df1
lyricists_name: Younsi, Ziri
lyricists_id: ZYOUN45
actors_name: Bracey, Alan
actors_id: ABBRA90
actors_role: owner
full_text_status: public
publication: The Astrophysical Journal Letters
volume: 964
number: 2
article_number: L26
issn: 2041-8205
citation:        Akiyama, K;    Alberdi, A;    Alef, W;    Algaba, JC;    Anantua, R;    Asada, K;    Azulay, R;                                                                                                                                                                                                                                                                                                                                                                                     ... Inoue, M; + view all <#>        Akiyama, K;  Alberdi, A;  Alef, W;  Algaba, JC;  Anantua, R;  Asada, K;  Azulay, R;  Bach, U;  Baczko, AK;  Ball, D;  Baloković, M;  Bandyopadhyay, B;  Barrett, J;  Bauböck, M;  Benson, BA;  Bintley, D;  Blackburn, L;  Blundell, R;  Bouman, KL;  Bower, GC;  Boyce, H;  Bremer, M;  Brinkerink, CD;  Brissenden, R;  Britzen, S;  Broderick, AE;  Broguiere, D;  Bronzwaer, T;  Bustamante, S;  Byun, DY;  Carlstrom, JE;  Ceccobello, C;  Chael, A;  Chan, CK;  Chang, DO;  Chatterjee, K;  Chatterjee, S;  Chen, MT;  Chen, Y;  Cheng, X;  Cho, I;  Christian, P;  Conroy, NS;  Conway, JE;  Cordes, JM;  Crawford, TM;  Crew, GB;  Cruz-Osorio, A;  Cui, Y;  Dahale, R;  Davelaar, J;  De Laurentis, M;  Deane, R;  Dempsey, J;  Desvignes, G;  Dexter, J;  Dhruv, V;  Dihingia, IK;  Doeleman, SS;  Dougall, S;  Dzib, SA;  Eatough, RP;  Emami, R;  Falcke, H;  Farah, J;  Fish, VL;  Fomalont, E;  Ford, HA;  Foschi, M;  Fraga-Encinas, R;  Freeman, WT;  Friberg, P;  Fromm, CM;  Fuentes, A;  Galison, P;  Gammie, CF;  García, R;  Gentaz, O;  Georgiev, B;  Goddi, C;  Gold, R;  Gómez-Ruiz, AI;  Gómez, JL;  Gu, M;  Gurwell, M;  Hada, K;  Haggard, D;  Haworth, K;  Hecht, MH;  Hesper, R;  Heumann, D;  Ho, LC;  Ho, P;  Honma, M;  Huang, CWL;  Huang, L;  Hughes, DH;  Ikeda, S;  Violette Impellizzeri, CM;  Inoue, M;   - view fewer <#>    (2024)    First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring.                   The Astrophysical Journal Letters , 964  (2)    , Article L26.  10.3847/2041-8213/ad2df1 <https://doi.org/10.3847/2041-8213%2Fad2df1>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10190893/1/The_Event_Horizon_Telescope_Collaboration_2024_ApJL_964_L26.pdf