Powering of cool filaments in cluster cores by buoyant bubbles. I. Qualitative model. (arXiv:1304.3168v1 [astro-ph.HE])

Powering of cool filaments in cluster cores by buoyant bubbles. I. Qualitative model. (arXiv:1304.3168v1 [astro-ph.HE]):
Cool-core clusters (e.g., Perseus or M87) often possess a network of bright
gaseous filaments, observed in radio, IR, optical and X-ray bands. We propose
that these filaments are powered by the reconnection of the magnetic field in
the wakes of buoyant bubbles. AGN-inflated bubbles of relativistic plasma rise
buoyantly in the cluster atmosphere, stretching and amplifying the field in the
wake to values of $\beta =8\pi P_{gas}/B^2\sim 1$. The field lines in the wake
have opposite directions and are forced together as the bubble motion stretches
the filament. This setup bears strong similarity to the coronal loops on the
Sun or the Earth magneto-tail. The reconnection process naturally explains both
the required level of local dissipation rate in filaments and the overall
luminosity of filaments. The original source of power for the filaments is the
potential energy of buoyant bubbles, inflated by the central AGN.