Submillimeter polarization and variability of quasar PKS 1830-211
Journal article, 2019

Polarization from active galactic nuclei is interpreted as a signpost of the role of magnetic fields in the launch and collimation of their relativistic radio jets. Here, we report the detection of a clear polarization signal from ALMA observations of the gravitationally lensed quasar PKS 1830-211 at submillimeter wavelengths (Band 9, 650 GHz). Applying a differential-polarimetry technique to the two compact lensed images of the quasar, we estimate a fractional polarization of ∼5% for one lensed image, while the other appears nearly unpolarized, which implies that the polarization activity varies on a timescale of a few weeks. With additional ALMA Band 7 and 8 (between 300-500 GHz) concomitant data, we constrain a Faraday rotation of a few 105 rad m-2. We also observe flux-density variability of 10% within one hour in Band 9. This work illustrates that a differential analysis can extract high-accuracy information (flux-density ratio and polarimetry) free of calibration issues from resolved sources in the submillimeter domain.

Quasars: individual: PKS 1830-211


Radio continuum: galaxies

Techniques: polarimetric


Ivan Marti-Vidal

Chalmers, Space, Earth and Environment, Onsala Space Observatory

S. Muller

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 621 A18

Subject Categories

Astronomy, Astrophysics and Cosmology

Signal Processing

Medical Image Processing



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