Constraining the Primordial Magnetic Fields

Speaker: Salome Mtchedlidze (University of Bologna) In Person and zoom 

Zoom info: https://stanford.zoom.us/j/98604058568

The magnetisaton of our universe on galaxy and galaxy cluster scales, and in the recent years revealed on filamentary scales as well, raises interest in understanding its origin. The blazar spectra observations provide an intriguing possibility of the existence of magnetic fields in cosmic voids. This motivates us not only to explore their origin but also to predict their structure on these vast scales, especially for the upcoming radio observations with Square Kilometer Array. If large-scale magnetism originates from fields generated in the late Universe — during reionization and structure formation — such fields could influence the magnetisation and possibly the evolution of the intracluster and intergalactic medium. On the other hand, if magnetic fields are primordial, generated in the pre-recombination Universe, they can naturally permeate the entire Universe and leave imprints on various cosmological phenomena (e.g., on the Cosmic Microwave Background and matter power spectra, propagation of high-energy gamma rays, relic gravitational waves, etc). In this talk, I will present results from our study where we explored the evolution of primordial magnetic fields with different structures on cosmic scales. I will then discuss implications of our findings for Rotation Measure (one of powerful probes of magnetic fields on galaxy cluster scales and in the intergalactic medium) analysis.