Cosmic magnetism with the Low Frequency Array, LOFAR

by Cathy Horellou (Chalmers University of Technology, Dept of Space, Earth and Environment, Onsala Space Observatory, Sweden)

Wednesday 4 May 2022, 13:30 → 14:30 Europe/Stockholm

https://stockholmuniversity.zoom.us/j/530682073

Magnetic fields exist in our Universe on multiple scales and in various environments. A powerful way to probe magnetized astrophysical plasmas is through radio-continuum observations of synchrotron emission. A key effect is the Faraday rotation of polarized radio waves that provides information on magneto-ionic media along the lines of sight toward distant sources. This effect is proportional to the wavelength squared, and observations at very long wavelengths (very low frequencies) and over a broad frequency range make it possible to achieve a much higher precision on the Rotation Measures (RM). I will review recent results and ongoing projects based on observations with the Low Frequency Array, LOFAR, at 150 MHz (2 meters wavelength). The combination of sensitivity, angular resolution, field of view and RM-precision of LOFAR makes it an outstanding instrument to investigate magnetism in a range of environments: from our own Milky Way to distant active galactic nuclei (some with associated radio jets and lobes), and also along the lines of sight toward polarized radio sources, to search for signatures of weak magnetic fields in the large-scale structure. This work is carried out within the LOFAR Magnetism Key Science Project (KSP), in collaboration with the LOFAR Surveys KSP.

Horellou_2022-05-04.mp4