We present results of deep 153 ks Chandra observations of the hot , 11 keV , galaxy cluster associated with the radio galaxy 3C 438 .
By mapping the morphology of the hot gas and analyzing its surface brightness and temperature distributions , we demonstrate the presence of a merger bow shock .
We identify the presence of two jumps in surface brightness and in density located at \sim 400 kpc and \sim 800 kpc from the cluster ’ s core .
At the position of the inner jump , we detect a factor of 2.3 \pm 0.2 density jump , while at the location of the outer jump , we detect a density drop of a factor of 3.5 \pm 0.7 .
Combining this with the temperature distribution within the cluster , we establish that the pressure of the hot gas is continuous at the 400 kpc jump , while there is a factor of 6.2 \pm 2.8 pressure discontinuity at 800 kpc jump .
From the magnitude of the outer pressure discontinuity , using the Rankine-Hugoniot jump conditions , we determine that the sub-cluster is moving at M = 2.3 \pm 0.5 , or approximately 2600 \pm 565 km/s through the surrounding intracluster medium , creating the conditions for a bow shock .
Based on these findings , we conclude that the pressure discontinuity is likely the result of an ongoing major merger between two massive clusters .
Since few observations of bow shocks in clusters have been made , this detection can contribute to the study of the dynamics of cluster mergers , which offers insight on how the most massive clusters may have formed .