088121

We propose to observe the outskirt along the merger equator of a cluster pair 1E 2216.0-0401 and 1E 2215.7- 0404. This is a textbook pre-merger system comma where a unique equatorial shock has been discovered using the recent XMM-Newton and Chandra observations proposed by the PI. We request a follow-up EPIC exposure of 140 ks to accurately measure the entropy distribution along the equatorial region to r200 comma and to search for other openParearlierclosePar equatorial shocks in the cluster outskirts. This observation will complete our view on the role played by equatorial shocks in energy transfer and circum-cluster heating during the cluster formation.