Universal Features of Magnetic Fields Near Kerr Black Holes / Backlighting the Cosmic Web with Fast Radio Bursts: First Measurements and Constraints

Zack Gelles examines how black-hole rotation twists magnetic fields near light cylinders, where plasma accelerates into inflows and outflows. Semi-analytic models and simulations connect this structure to polarization changes detectable with radio interferometry, offering constraints on black-hole spin and relativistic jets. Kritti Sharma presents fast radio bursts as probes of cosmic baryons. Dispersion measures and secure host redshifts constrain gas in galaxy groups and clusters, while correlations with large-scale structure and other tracers map matter along burst sight-lines. The talk considers how future burst surveys can measure baryonic feedback and its evolution alongside other cosmological observations.