We utilize cosmological simulations of 16 galaxy clusters at redshifts z = 0 and z = 0.6 to study the effect of inflowing streams on the properties of the X-ray emitting intracluster medium. We find that the mass accretion occurs predominantly along streams that originate from the cosmic web and consist of heated gas. Clusters that are unrelaxed in terms of their X-ray morphology are characterized by higher mass inflow rates and deeper penetration of the streams, typically into the inner third of the virial radius. The penetrating streams generate elevated random motions, bulk flows and cold fronts. The degree of penetration of the streams may change over time such that clusters can switch from being unrelaxed to relaxed over a time-scale of several giga years.
Bibliographical noteFunding Information:
ACKNOWLEDGEMENTS We acknowledge stimulating discussions with Nir Shaviv and Alexey Vikhlinin. This work was partly supported by the grants ISF 124/12, I-CORE Program of the PBC/ISF 1829/12, BSF 2014-273, and NSF AST-1405962.
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
- Galaxies: clusters: general
- Galaxies: clusters: intracluster medium