Modern, large-area sky surveys at decametre to decimetre wavelengths have begun to reveal the widespread presence of magnetised plasma in the intergalactic medium, transported from SMBHs through relativistic jets. Even more sensitive surveys, such as those possible with LOFAR 2, the DSA-2000, and the SKA, will likely uncover many larger and older plasma deposits, from the Local Universe to the first gigayears. Porphyrion, a recently discovered 7 Mpc long jetted structure that formed in the first half of cosmic time, may provide a glimpse of what future observations shall yield. Classically, jet plasma is thought to stay trapped within galaxy clusters and filaments of the Cosmic Web, where diffusion is ineffective. However, systems like Porphyrion appear to demonstrate that jets can carry magnetised plasma all the way into cosmic voids (~90% of the Universe by volume) — which are conventionally seen as pristine enough to retain signatures of primordial magnetism.

In this talk, I will discuss observations of Porphyrion and similar sources, which suggest that cosmic voids may have been magnetised by Mpc-scale jets.

For Zoom connection information, please contact Brian C. Lemaux (brian.lemaux_at_noirlab.edu).