Ann Mao (MPIfR, Germany)

Detecting magnetic fields in distant galaxies with broadband radio polarimetry
When Jan 25, 2018 from 02:30 PM to 03:30 PM
What
  • Colloquium
Where SH Lecture Hall
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Even though magnetic fields play crucial roles in galaxies from sub-parsec to kilo-parsec scales, how galaxies and their magnetic fields have co-evolved since the early universe remains an unsolved fundamental question in cosmology and astro-plasma physics due to the lack of magnetic field measurements beyond the local universe. In this talk, I will first describe how the advent of broadband radio polarimetric observations have revolutionized the field of cosmic magnetism by enabling the derivation of properties of magnetic fields in astrophysical objects that were impossible to obtain previously with narrowband data. I will then demonstrate how broadband polarimetry, in combination with innovative observational methods can allow us to, for the first time, measure magnetic fields in galaxies in previously uncharted redshift regimes. In particular, I will report our record-holder detection of μG coherent magnetic fields in a disk galaxy as seen 4.6 Gyrs ago by taking advantage of gravitational lensing. I will conclude by discussing prospects of upcoming polarimetric surveys to be conducted with Square Kilometre Array pathfinders and the eventual Square Kilometre Array.