Self-consistent evolution of gas and cosmic rays in Cygnus A and similar FR II classic double radio sources

Abstract

In Cygnus A and other classical FR II double radio sources, powerful opposing jets from the cores of halo-centered galaxies drive out into the surrounding cluster gas, forming hotspots of shocked and compressed cluster gas at the jet extremities. The moving hotspots are sandwiched between two shocks. An inner-facing shock receives momentum and cosmic rays from the jet and creates additional cosmic rays that form a radio lobe elongated along the jet axis. An outer-facing bow shock moves directly into the undisturbed group or cluster gas, creating a cocoon of shocked gas enclosing the radio lobe. We describe computations that follow the self-consistent dynamical evolution of the shocked cluster gas and the relativistic synchrotron-emitting gas inside the lobes. Relativistic and non-relativistic components exchange momentum by interacting with small magnetic fields having dynamically negligible energy densities. The evolution of Cygnus A is governed almost entirely by cosmic ray energy flowing from the hotspots. Mass flowing into hotspots from the jets is assumed to be small, greatly reducing the mass of gas flowing back along the jet, common in previous calculations, that would disrupt the spatial segregation of synchrotron-loss ages observed inside FR II radio lobes. We compute the evolution of the cocoon when the velocity and cosmic ray luminosity of the hotspots are constant and when they vary with time. If cosmic rays mix with cluster gas in hotspots before flowing into the radio lobe, the thermal gas is heated to mildly relativistic temperatures, producing an unobserved pressure inside the lobe.

ApJ accepted, 23 pages, 12 figures

References in corpus (8)

• The Black Hole Mass, Stellar M/L, and Dark Halo in M87
• The Cavity of Cygnus A
• Physical Properties of Very Powerful FRII Radio Galaxies
• A method of estimation of the dynamical age of FR II-type radio sources from multifrequency data
• Chandra Reveals Twin X-ray Jets in the Powerful FR-II Radio Galaxy 3C353
• The Fate of Young Radio Galaxies: Decelerations Inside Host Galaxies?
• Energetics of X-ray Cavities and Radio Lobes in Galaxy Clusters
• Stopping Cooling Flows with Cosmic Ray Feedback

Cited by in corpus (10)

• The Fermi Bubbles. I. Possible Evidence for Recent AGN Jet Activity in the Galaxy
• The Cocoon Shocks of Cygnus A: Pressures and Their Implications for the Jets and Lobes
• Reversing cooling flows with AGN jets: shock waves, rarefaction waves, and trailing outflows
• On the Importance of Very-light Internally-subsonic AGN Jets in Radio-mode AGN Feedback
• On the Interaction of the PKS B1358-113 Radio Galaxy with the Abell 1836 Cluster
• The X-ray Ribs Within the Cocoon Shock of Cygnus A
• Two-temperature Magnetohydrodynamic simulations for sub-relativistic AGN jets:Dependence on the fraction of the electron heating
• Dynamics Inside the Radio and X-ray Cluster Cavities of Cygnus A and Similar FRII Sources
• Non-thermal emission in lobes of radio galaxies: III. 3C 98, Pictor A, DA 240, Cygnus A, 3C 326, and 3C 236
• First Dynamic Computation of Synchrotron Emission from the Cygnus A Radio Cavity; Evidence for Electron Pair Plasma in Cavity