Due to their late formation in cosmic history, clusters of galaxies are not fully in hydrostatic equilibrium and the gravitational pull of their mass at a given radius is expected not to be entirely balanced by the thermal gas pressure. Turbulence may supply additional pressure, and recent (X-ray and SZ) hydrostatic mass reconstructions claim a pressure support of ∼5-15 per cent of the total pressure at R 200 . In this work we show that, after carefully disentangling bulk from small-scale turbulent motions in high-resolution simulations of galaxy clusters, we can constrain which fraction of the gas kinetic energy effectively provides pressure support in the cluster's gravitational potential. While the ubiquitous presence of radial inflows in the cluster can lead to significant bias in the estimate of the non-thermal pressure support, we report that only a part of this energy effectively acts as a source of pressure, providing a support of the order of ∼10 per cent of the total pressure at R 200.
|Original language||English (US)|
|Journal||Monthly Notices of the Royal Astronomical Society: Letters|
|State||Published - Nov 21 2018|
Bibliographical noteFunding Information:
We wish to dedicate this work to the memory of Giuseppe (Bepi) Tormen, who tragically passed away on June 2018, and first introduced FV to cosmological simulations and the beautiful mess they contain. We used the ENZO code (http://enzo-project.org), the product of a collaborative effort of scientists at many universities and national laboratories. We thank our reviewer, E. Churazov, for useful comments which improved the quality of our work, and A. Bonafede for performing the calculation of X-ray morphological parameters. FV acknowledges financial support from the Horizon 2020 program under the ERC Starting Grant 'MAGCOW', no. 714196. TWJ acknowledges support from the US National Science Foundation. The simulations were carried out at the Minnesota Supercomputing Institute at the University of Minnesota.
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
- Galaxy: general
- Intergalactic medium
- Large-scale structure of Universe
- Methods: numerical