  We present joint X-ray and optical observations of the high redshift (z~0.83)
lensing cluster CLJ0152.7-1357 made with the Chandra X-ray Observatory and the
Keck telescope. We confirm the existence of significant substructure at both
X-ray and optical wavelengths in the form of two distinct clumps, whose
temperatures are 6.6(-1.5,+2.4) keV and 5.7(-1.6,+2.9) keV, respectively. The
X-ray surface brightness profiles of the two clumps can be fitted by either a
single beta-model or an NFW-like profile; the latter giving better fits to the
central regions. We find that the X-ray derived mass of this cluster is in good
agreement with independent lensing measurements. While its appearance indicates
that the cluster has not reached a dynamical equilibrium state, its X-ray
luminosity L_x, temperature T and dynamical mass M are consistent with the
well-defined L_x-T and M-T relations for low-redshift galaxy clusters, which
suggests that the dynamical properties of the clusters have remained almost
unchanged since z~0.8.
