Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-06-11
Astronomy and Astrophysics
Astrophysics
6 pages, LaTeX2e, to appear in `Diffuse Thermal and Relativistic Plasma in Galaxy Clusters', 1999, Ringberg Workshop, Germany,
Scientific paper
We investigate the possibility that patches of old radio plasma (`radio ghosts') of former radio galaxies form a second distinct phase of the inter-galactic medium (IGM), not mixed with the thermal gas. The separation of this phase from the ambient gas and its resistance against eroding turbulent forces is given by magnetic fields, which are expected to be roughly in pressure equilibrium with the surrounding medium. Since patches of this plasma are largely invisible in the radio we use the term `radio ghost' to characterize their nature. Possibilities and difficulties of different detection strategies of ghosts are discussed. These involve radio emission, cosmic microwave background (CMB) and starlight Comptonization, and Faraday rotation. Re-activation of the electron population in shock waves of cosmological structure formation, which seems to lead to the cluster radio relic phenomena. We discuss the role radio ghosts can have: They are able to store relativistic particles for cosmological times, but are also able to release them under the influence of very strong turbulence. This might happen during a major merger event of clusters of galaxies. The released relativistic proton population could produce the observed radio halos of some cluster of galaxies via hadronic reactions with the background gas leading to the production of secondary electrons and positrons. Destroyed ghosts, mixed with the IGM can help to magnetize it. Finally, the strong field strength within ghosts should have a significant impact on the propagation of extragalactic high energy cosmic rays.
No associations
LandOfFree
Radio Ghosts does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Radio Ghosts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radio Ghosts will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-251810