We set limits on the presence of the synchrotron cosmic web through the cross-correlation of the 2.3 GHz S-PASS survey with a model of the local cosmic web derived from constrained magnetohydrodynamic (MHD) simulations. The MHD simulation assumes cosmologically seeded magnetic fields amplified during large-scale structure formation, and a population of relativistic electrons/positrons from proton-proton collisions within the intergalactic medium. We set a model-dependent 3σ upper limit on the synchrotron surface brightness of 0.16 mJy arcmin−2 at 2.3 GHz in filaments. Extrapolating from magnetic field maps created from the simulation, we infer an upper limit (density-weighted) magnetic field of 0.03 (0.13) μG in filaments at the current epoch, and a limit on the primordial magnetic field (PMF) of BPMF~1.0 nG.
@article{arxiv.1703.07829,
title = {Limiting Magnetic Fields in the Cosmic Web with Diffuse Radio Emission},
author = {S. Brown and T. Vernstrom and E. Carretti and K. Dolag and B. M. Gaensler and L. Staveley-Smith and G. Bernardi and M. Haverkorn and M. Kesteven and S. Poppi},
journal= {arXiv preprint arXiv:1703.07829},
year = {2017}
}