Deep XMM-Newton Observations of the NW Radio Relic Region of Abell 3667

Understand

The results of long XMM-Newton X-ray observations of the NW radio relic of Abell 3667 are presented.

• A shock is detected at the sharp outer edge of the radio relic, both in the X-ray surface brightness and the temperature profiles.
• The Mach number is M = 2.54^+0.80_-0.43.
• The temperature jump at the shock is larger than expected from the density jump, which may indicate that a dynamically important magnetic field aligned primarily parallel to the shock front is present.