Simulated Interactions Between Radio Galaxies and Cluster Shocks — 2: Jet Axes Orthogonal to Shock Normals. (arXiv:1909.08721v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nolting_C/0/1/0/all/0/1">Chris Nolting</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jones_T/0/1/0/all/0/1">T. W. Jones</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+ONeill_B/0/1/0/all/0/1">Brian O'Neill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mendygral_P/0/1/0/all/0/1">P. J. Mendygral</a>
We report a 3D MHD simulation study of the interactions between radio
galaxies and galaxy-cluster-media shocks in which the incident shock normals
are orthogonal to the bipolar AGN jets. Before shock impact, light, supersonic
jets inflate lobes (cavities) in a static, uniform ICM. We examine three AGN
activity scenarios: 1) continued, steady jet activity; 2) jet source cycled off
coincident with shock/radio lobe impact; 3) jet activity ceased well before
shock arrival (a “radio phoenix” scenario). The simulations follow relativistic
electrons (CRe) introduced by the jets, enabling synthetic radio synchrotron
images and spectra. Such encounters can be decomposed into an abrupt shock
transition and a subsequent long term post shock wind. Shock impact disrupts
the pre-formed, low density RG cavities into two ring vortices embedded in the
post shock wind. Dynamical processes cause the vortex pair to merge as they
propagate downwind somewhat faster than the wind itself. When the AGN jets
remain active ram pressure bends the jets downwind, generating a narrow angle
tail morphology aligned with the axis of the vortex ring. The deflected jets do
not significantly alter dynamical evolution of the vortex ring. However, active
jets and their associated tails do dominate the synchrotron emission,
compromising the observability of the vortex structures. Downwind-directed
momentum concentrated by the jets impacts and alters the post-encounter shock.
In the “radio phoenix” scenario, no DSA of the fossil electron population is
required to account for the observed brightening and flattening of the spectra,
adiabatic compression effects are sufficient.
We report a 3D MHD simulation study of the interactions between radio
galaxies and galaxy-cluster-media shocks in which the incident shock normals
are orthogonal to the bipolar AGN jets. Before shock impact, light, supersonic
jets inflate lobes (cavities) in a static, uniform ICM. We examine three AGN
activity scenarios: 1) continued, steady jet activity; 2) jet source cycled off
coincident with shock/radio lobe impact; 3) jet activity ceased well before
shock arrival (a “radio phoenix” scenario). The simulations follow relativistic
electrons (CRe) introduced by the jets, enabling synthetic radio synchrotron
images and spectra. Such encounters can be decomposed into an abrupt shock
transition and a subsequent long term post shock wind. Shock impact disrupts
the pre-formed, low density RG cavities into two ring vortices embedded in the
post shock wind. Dynamical processes cause the vortex pair to merge as they
propagate downwind somewhat faster than the wind itself. When the AGN jets
remain active ram pressure bends the jets downwind, generating a narrow angle
tail morphology aligned with the axis of the vortex ring. The deflected jets do
not significantly alter dynamical evolution of the vortex ring. However, active
jets and their associated tails do dominate the synchrotron emission,
compromising the observability of the vortex structures. Downwind-directed
momentum concentrated by the jets impacts and alters the post-encounter shock.
In the “radio phoenix” scenario, no DSA of the fossil electron population is
required to account for the observed brightening and flattening of the spectra,
adiabatic compression effects are sufficient.
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