X-ray observations of clusters of galaxies reveal the presence of edges in surface brightness and temperature, known as "cold fronts". In relaxed clusters with cool cores, these commonly observed edges have been interpreted as evidence for the "sloshing" of the core gas in the cluster's gravitational potential. Such sloshing may provide a source of heat to the cluster core by mixing hot gas from the cluster outskirts with the cool core gas. Using high-resolution $N$-body/Eulerian hydrodynamics simulations, we model gas sloshing in galaxy clusters initiated by mergers with subclusters. The simulations include merger scenarios with gas-filled and gasless subclusters. The effect of changing the viscosity of the intracluster medium is also explored. We find that sloshing can facilitate heat inflow to the cluster core, provided that there is a strong enough disturbance. In adiabatic simulations, we find that sloshing can raise the entropy floor of the cluster core by nearly an order of magnitude in the strongest cases. If the ICM is viscous, the mixing of gases with different entropies is decreased and consequently the heat flux to the core is diminished. In simulations where radiative cooling is included, we find that though eventually a cooling flow develops, sloshing can prevent the significant buildup of cool gas in the core for times on the order of a Gyr for small disturbances and a few Gyr for large ones. If repeated encounters with merging subclusters sustain the sloshing of the central core gas as is observed, this process can provide a relatively steady source of heat to the core, which can help to prevent a significant cooling flow.
Effects of Viscosity on Sloshing Cold Fronts in Galaxy Clusters
National Tsing Hua University（国立清华大学）；Center for Astrophysics | Harvard & Smithsonian（哈佛-史密森尼天体物理中心）；National Center for Theoretical Sciences（国家理论科学中心）
Centre for Space Research, North-West University（西北大学空间研究中心）；National Centre for Radio Astrophysics (NCRA), Tata Institute of Fundamental Research (TIFR)（塔塔基础研究院国家射电天文学中心）；National Institute for Theoretical and Computational Sciences (NITheCS)（理论与计算科学国立研究所）；Dayanand Science College（戴亚南德理学院）
A "MeerKAT-meets-LOFAR" Study of 2A 0335+096: Discovery of a Complex 500 kpc Radio Halo in a Disturbed Cool-Core Cluster
Astronomisches Institut der Ruhr-Universität Bochum（波鸿鲁尔大学天文研究所）；Ruhr Astroparticle and Plasma Physics Center（鲁尔天体粒子与等离子体物理中心）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；INAF – IASF Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano（意大利国家天体物理研究所-米兰空间天体物理学和宇宙物理学研究所）；Institute for Computational Cosmology, Department of Physics, Durham University（杜伦大学物理系计算宇宙学研究所）；INAF – Istituto di Radioastronomia（意大利国家天体物理研究所-射电天文学研究所）；Dipartimento di Fisica e Astronomia, Università di Bologna（博洛尼亚大学物理与天文学系）；Astronomical Institute of the Czech Academy of Sciences（捷克科学院天文研究所）；Thuringer Landessternwarte（图林根州立天文台）
