  Previous studies of the massive nearby galaxy cluster Abell 3558 reported a
cold front around the cluster core, which is attributed to the sloshing of the
core as it responds to the gravitational disturbance created by a past minor
merger. Here, using XMM-Newton mosaic, we report the detection of two rare
large-scale sloshing cold fronts far outside the cooling radius of Abell 3558.
One of the detected cold fronts is located 600 kpc from the cluster core to the
south-east, while the other is located 1.2 Mpc from the cluster core to the
north-west. The latter cold front is one of the most distant cold fronts ever
observed in a galaxy cluster. Our findings are in agreement with previous
studies that sloshing can extend well beyond the cooling radius, on scales
exceeding half the virial radius, suggesting that sloshing is a cluster-wide
phenomenon and may affect the cluster's global properties.
