Linear polarization in the nucleus of M87 at 7 mm and 1.3 cm

Abstract

We report on high angular resolution polarimetric observations of the nearby radio galaxy M87 using the Very Long Baseline Array at 24 GHz ($\lambda =$1.3 cm) and 43 GHz ($\lambda =$7 mm) in 2017-2018. New images of the linear polarization substructure in the nuclear region are presented, characterized by a two-component pattern of polarized intensity and smooth rotation of the polarization plane around the 43 GHz core. From a comparison with an analogous dataset from 2007, we find that this global polarization pattern remains stable on a time interval of 11 yr, while showing smaller month-scale variability. We discuss the possible Faraday rotation toward the M87 nucleus at centimeter to millimeter wavelengths. These results can be interpreted in a scenario where the observed polarimetric pattern is associated with the magnetic structure in the confining magnetohydrodynamic wind, which also serves as the source of the observed Faraday rotation.

9 pages, including 4 pages of Appendix; published in A&A Letters

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Cited by in corpus (27)

• First M87 Event Horizon Telescope Results. VII. Polarization of the Ring
• Polarimetric properties of Event Horizon Telescope targets from ALMA
• Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
• Reading M87's DNA: A Double Helix revealing a large scale Helical Magnetic Field
• The Accretion flow in M87 is really MAD
• Properties of the jet in M87 revealed by its helical structure imaged with the VLBA at 8 and 15 GHz
• Modeling the inner part of the jet in M87: Confronting jet morphology with theory
• Polarization calibration techniques for new-generation VLBI
• Broadband Multi-wavelength Properties of M87 during the 2018 EHT Campaign including a Very High Energy Flaring Episode
• Positron Effects on Polarized Images and Spectra from Jet and Accretion Flow Models of M87* and Sgr A*
• Spectral analysis of a parsec-scale jet in M87: Observational constraint on the magnetic field strengths in the jet
• RadioAstron Space VLBI Imaging of the jet in M87: I. Detection of high brightness temperature at 22 GHz
• M87: a cosmic laboratory for deciphering black hole accretion and jet formation
• Black Holes Up Close
• Signatures of Black Hole Spin and Plasma Acceleration in Jet Polarimetry
• Polarization Observations of AGN Jets: Past and Future
• CLEAN imaging systematics of M87 radio jet
• Matter density distribution of general relativistic highly magnetized jets driven by black holes
• First polarization study of the M87 jet and active galactic nuclei at submillimeter wavelengths with ALMA
• Survey of Non-thermal Electron around Supermassive Black Holes through Polarization Flips
• Electromagnetic signatures of strong-field gravity from accreting black holes
• Imaging the event horizon of M87* from space on different timescales
• Message in a Bottle: Unveiling the Magneto-Ionic Complexity of AGNs through the Stokes QU-Fitting Technique
• Low optical polarisation at the core of the optically-thin jet of M87
• Characterization of black hole accretion through image moment invariants
• A revised view of the linear polarization in the subparsec core of M87 at 7 mm
• Investigating the Disk-Jet Structure in M87 through Flux Separation in the Linear and Circular Polarization Images