2021MNRAS.502..423S -
Mon. Not. R. Astron. Soc., 502, 423-435 (2021/March-3)
Three-dimensional simulations of X-ray cavities inflated by radio galaxies.
SMITH M.D. and DONOHOE J.
Abstract (from CDS):
Vast cavities in the intergalactic medium are excavated by radio galaxies. The cavities appear as such in X-ray images because the external medium has been swept-up, leaving a hot but low-density bubble surrounding the radio lobes. We explore here the predicted thermal X-ray emission from a large set of high-resolution three-dimensional simulations of radio galaxies driven by supersonic jets. We assume adiabatic non-relativistic hydrodynamics with injected straight and precessing jets of supersonic gas emitted from nozzles. Images of X-ray bremsstrahlung emission tend to generate oval cavities in the soft keV bands and leading arcuate structures in hard X-rays. However, the cavity shape is sensitive to the jet-ambient density contrast, varying from concave-shaped at η = 0.1 to convex for η = 0.0001 where η is the jet/ambient density ratio. We find lateral ribs in the soft X-rays in certain cases and propose this as an explanation for those detected in the vicinity of Cygnus A. In bi-lobed or X-shaped sources and in curved or deflected jets, the strongest X-ray emission is not associated with the hotspot but with the relic lobe or deflection location. This is because the hot high-pressure and dense high-compression regions do not coincide. Directed towards the observer, the cavity becomes a deep round hole surrounded by circular ripples. With short radio-mode outbursts with a duty cycle of 10 per cent, the intracluster medium simmers with low Mach number shocks widely dissipating the jet energy in between active jet episodes.
Abstract Copyright:
© 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
hydrodynamics - galaxies: active - galaxies: jets - radio continuum: galaxies
CDS comments:
MS0375 is a misprint for MS0735 (ClG 0735+74 in SIMBAD).
Simbad objects:
11
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