The rotation measures of high luminosity sources as seen from the NVSS

Understand

We re-analyse the subset of the Faraday rotation measures data from the NRAO VLA Sky Survey catalogue for which redshift and spectral index information is available, in order to better elucidate the relations between these observables.

• We split this subset in two based on their radio luminosity, and find that higher power sources have a systematically higher residual rotation measure, once the regular field of the Milky Way is subtracted.
• This rotation measure stands well above the variances due to the turbulent field of our Galaxy and measurement errors, contrarily to low power sources.
• The effect is more pronounced as the energy threshold becomes more restrictive.