Gas perturbations in cool cores of galaxy clusters: effective equation of state, velocity power spectra and turbulent heating

Understand

We present the statistical analysis of X-ray surface brightness and gas density fluctuations in cool cores of ten, nearby and bright galaxy clusters that have deep Chandra observations and show observational indications of radio-mechanical AGN feedback.

• Within the central parts of cool cores the total variance of fluctuations is dominated by isobaric and/or isothermal fluctuations on spatial scales ~ 10-60 kpc, which are likely associated with slow gas motions and bubbles of relativistic plasma.
• Adiabatic fluctuations associated with weak shocks constitute less than 10 per cent of the total variance in all clusters.
• The typical amplitude of density fluctuations is small, ~ 10 per cent or less on scales of ~ 10-15 kpc.