Faraday Rotation Measure due to the Intergalactic Magnetic Field II: the Cosmological Contribution

Understand

We investigate the Faraday rotation measure (RM) due to the intergalactic magnetic field (IGMF) through the cosmic web up to cosmological distances, using a model IGMF based on turbulence dynamo in the large-scale structure of the universe.

• By stacking the IGMF and gas density data up to redshift $z=5$ and taking account of the redshift distribution of polarized background radio sources against which the RM is measured, we simulate the sky map of the RM.
• The contribution from galaxy clusters is subtracted from the map, based on several different criteria of X-ray brightness and temperature.
• Our findings are as follows.