2-6 September 2024
CJD Bonn Castell
Europe/Berlin timezone
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Contribution

CJD Bonn Castell

MOJAVE XXII: The Spatial and Temporal Evolution of Faraday Rotation in AGN jets

Speakers

  • Dr. Jack LIVINGSTON

Primary authors

Content

Active Galactic Nuclei (AGN) generate extreme luminosities, and their central engines have strong magnetic fields and high electron densities which play a major role in the formation of relativistic jets. The Faraday Rotation (FR) MOJAVE project presents resolved polarimetric images of 25 AGN derived from 15/24/43 GHz observations using the Very Long Baseline Array (VLBA). These span across 23 epochs between August 2019 to June 2021, giving us a unique view into both the spatial and temporal evolution of the magneto-ionic media of AGN. We derive FR, intrinsic electric vector position angle (EVPA), spectral index, and depolarisation maps. For “quasar” jets, we see longitudinal magnetic fields, whereas for “BL Lac objects” we see transverse jet magnetic fields indicative of shocks. We find that AGN cores have large FR values that are highly spatially and temporally variable. At variable times core regions also show evidence for non-lambda2 dependent FR, which is suggestive of FR internal to the emission of the source. By combining depolarisation and FR information we find further evidence of internal FR and find a collection of sources that show a transition between internal and external FR between the core and jet regions, which change over time, allowing us to unravel the nature of their magneto-ionic environments.