Abstract
A combination of 3D magnetohydrodynamics and synthetic numerical simulations are presented
to follow the evolution of a randomly magnetized plasma that models the intracluster
medium, under the isolated effects of powerful, light, hypersonic and bipolar Fanaroff–Riley
class II jets. We prescribe the cluster magnetic field (CMF) as a Gaussian random field with
a Kolmogorov-like energy spectrum. Both the power of the jets and the viewing angle that is
used for the synthetic rotation measure (RM) observations are investigated. We find the model
radio sources introduce and amplify fluctuations on the RM statistical properties which we
analyse as a function of time as well as the viewing angle. The average RM and the RM standard
deviation are increased by the action of the jets. Energetics, RM statistics and magnetic
power spectral analysis consistently show that the effects also correlate with the jets’ power,
and that the lightest, fastest jets produce the strongest changes in their environment. We see
jets distort and amplify the CMFs especially near the edges of the lobes and the jets’ heads.
This process leads to a flattening of the RM structure functions at scales comparable to the
source size. The edge features we find are similar to ones observed in Hydra A. The results
show that jet-produced RM enhancements are more apparent in quasars than in radio galaxies.
Globally, jets tend to enhance the RM standard deviation which may lead to overestimations
of the CMFs’ strength by about 70 per cent. This study means to serve as a pathfinder for the
SKA, EVLA and LOFAR to follow the evolution of cosmic magnetic fields.
to follow the evolution of a randomly magnetized plasma that models the intracluster
medium, under the isolated effects of powerful, light, hypersonic and bipolar Fanaroff–Riley
class II jets. We prescribe the cluster magnetic field (CMF) as a Gaussian random field with
a Kolmogorov-like energy spectrum. Both the power of the jets and the viewing angle that is
used for the synthetic rotation measure (RM) observations are investigated. We find the model
radio sources introduce and amplify fluctuations on the RM statistical properties which we
analyse as a function of time as well as the viewing angle. The average RM and the RM standard
deviation are increased by the action of the jets. Energetics, RM statistics and magnetic
power spectral analysis consistently show that the effects also correlate with the jets’ power,
and that the lightest, fastest jets produce the strongest changes in their environment. We see
jets distort and amplify the CMFs especially near the edges of the lobes and the jets’ heads.
This process leads to a flattening of the RM structure functions at scales comparable to the
source size. The edge features we find are similar to ones observed in Hydra A. The results
show that jet-produced RM enhancements are more apparent in quasars than in radio galaxies.
Globally, jets tend to enhance the RM standard deviation which may lead to overestimations
of the CMFs’ strength by about 70 per cent. This study means to serve as a pathfinder for the
SKA, EVLA and LOFAR to follow the evolution of cosmic magnetic fields.
| Original language | English |
|---|---|
| Pages (from-to) | 1621-1639 |
| Number of pages | 19 |
| Journal | Monthly Notices of the Royal Astronomical Society (MNRAS) |
| Volume | 418 |
| Early online date | 6 Dec 2011 |
| DOIs | |
| Publication status | Published - 11 Dec 2011 |
Keywords
- MHD, turbulence, methods: numerical, galaxies: active, intergalactic medium, galaxies: jets