The Deep Polarized Sky

M304 (Maths, UCT)
Thu, 20/09/2012 - 13:00 - 14:00
Russ Taylor

Deep spectro-polarimetric imaging of the sky at 1.4 GHz with the Dominion Radio Astrophysical Observatory Synthesis Telescope has revealed an increase in the average fractional polarization of AGN integrated radio emission that continues to the sub-mJy regime. The deep polarization sky thus presents a puzzle that cannot be understood by simple extrapolation of the polarization properties of the strong AGN source population. At the same time observations and modeling of integrated polarized radio emission from disk galaxies is revealing significant polarized signals, and suggests that the evolution of the global properties of the magnetic fields in galaxy disks can be traced through statistical analyses of integrated polarization. Deep wide-field, spectro-polarimetric imaging surveys with our current largest telescopes, and planned with MeerKAT, promise to a) probe the polarization of the faint AGN population, b) allow measurements of the magnetic field properties in disk galaxies out to high redshift, and c) detect evidence of the cosmic magnetic web via propagation effects. All are key investigations in the effort to probe the evolution of cosmic magnetic fields.