Speaker
Description
Cosmic magnetic fields permeate environments from the interstellar medium to galaxies and large-scale structure, yet their origin and three-dimensional organization remain poorly understood. I present a framework that leverages radio polarimetric observations to directly measure magnetic helicity—a measure of magnetic topology that is more robustly conserved than magnetic energy and therefore retains memory of field generation. This provides a new diagnostic for distinguishing between magnetogenesis scenarios, including primordial mechanisms that may imprint large-scale, coherent chirality and astrophysical processes such as dynamos that generate scale-dependent helicity with characteristic sign reversals.
Applying this method to GMIMS High-band South (STAPS) data and the all-sky Faraday depth map of Hutschenreuter et al. (2020), we show that existing observations can be repurposed to access magnetic helicity, probing the three-dimensional topology of magnetic fields. The framework is broadly applicable across current and forthcoming radio polarization surveys (e.g., GMIMS, CHIME, LOFAR, ASKAP/POSSUM,and SKA).
This connection between observables and magnetic helicity opens a pathway to constraining the origin and evolution of cosmic magnetic fields.
