First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
Name:
Akiyama_2021_ApJL_910_L12.pdf
Size:
7.155Mb
Format:
PDF
Description:
Final Published Version
Affiliation
Steward Observatory and Department of Astronomy, University of ArizonaData Science Institute, University of Arizona
Issue Date
2021
Metadata
Show full item recordPublisher
American Astronomical SocietyCitation
Akiyama, K., Algaba, J. C., Alberdi, A., Alef, W., Anantua, R., Asada, K., ... & Nagai, H. (2021). First M87 Event Horizon Telescope Results. VII. Polarization of the Ring. The Astrophysical Journal Letters, 910(1), L12.Journal
Astrophysical Journal LettersRights
Copyright © 2021 The Author(s). Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located in the southwest part of the ring, where it rises to the level of ∼15%. The polarization position angles are arranged in a nearly azimuthal pattern. We perform quantitative measurements of relevant polarimetric properties of the compact emission and find evidence for the temporal evolution of the polarized source structure over one week of EHT observations. The details of the polarimetric data reduction and calibration methodology are provided. We carry out the data analysis using multiple independent imaging and modeling techniques, each of which is validated against a suite of synthetic data sets. The gross polarimetric structure and its apparent evolution with time are insensitive to the method used to reconstruct the image. These polarimetric images carry information about the structure of the magnetic fields responsible for the synchrotron emission. Their physical interpretation is discussed in an accompanying publication. © 2021. The Author(s). Published by the American Astronomical Society..Note
Open access articleISSN
2041-8205Version
Final published versionae974a485f413a2113503eed53cd6c53
10.3847/2041-8213/abe71d
Scopus Count
Collections
Except where otherwise noted, this item's license is described as Copyright © 2021 The Author(s). Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.