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Title: Circular Polarization of Simulated Images of Black Holes
Abstract Models of the resolved Event Horizon Telescope (EHT) sources Sgr A* and M87* are constrained by observations at multiple wavelengths, resolutions, polarizations, and time cadences. In this paper, we compare unresolved circular polarization (CP) measurements to a library of models, where each model is characterized by a distribution of CP over time. In the library, we vary the spin of the black hole, the magnetic field strength at the horizon (i.e., both SANE and magnetically arrested disk or MAD models), the observer inclination, a parameter for the maximum ion–electron temperature ratio assuming a thermal plasma, and the direction of the magnetic field dipole moment. We find that Atacama Large Millimeter/submillimeter Array (ALMA) observations of Sgr A* are inconsistent with all edge-on (i= 90°) models. Restricting attention to the MAD models favored by earlier EHT studies of Sgr A*, we find that only models with magnetic dipole moment pointing away from the observer are consistent with ALMA data. We also note that in 26 of the 27 passing MAD models, the accretion flow rotates clockwise on the sky. We provide a table of the means and standard deviations of the CP distributions for all model parameters, along with their trends.  more » « less
Award ID(s):
2034306
PAR ID:
10563634
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Astrophysical Journal
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
972
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
135
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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