E. Roediger, L. Lovisari, R. Dupke, S. Ghizzardi, M. Brüggen, R. P. Kraft, M. E. Machacek
We investigate the origin and nature of the multiple sloshing cold fronts in
the core of Abell 496 by direct comparison between observations and dedicated
hydrodynamical simulations. Our simulations model a minor merger with a
4{\times}10^13M{\circ} subcluster crossing A496 from the south-west to the
north-north-east, passing the cluster core in the south-east at a pericentre
distance 100 to a few 100 kpc about 0.6 to 0.8 Gyr ago. The gas sloshing
triggered by the merger can reproduce almost all observed features, e.g. the
characteristic spiral-like brightness residual distribution in the cluster
centre and its asymmetry out to 500 kpc, also the positions of and contrasts
across the cold fronts. If the subcluster passes close (100 kpc) to the cluster
core, the resulting shear flows are strong enough to trigger Kelvin-Helmholtz
instabilities that in projection resemble the peculiar kinks in the cold fronts
of Abell 496. Finally, we show that sloshing does not lead to a significant
modification of the global ICM profiles but a mild oscillation around the
initial profiles.
View original:
http://arxiv.org/abs/1112.1407
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