Discovery of X-ray emission from the distant lensing cluster of galaxies Cl 2236-04 at z=0.552

X-ray emission from the distant lensing cluster Cl 2236 - 04 at z = 0.552 w as discovered by ASCA and ROSAT/HRI observations. If the spherical symmetri c mass distribution model of the cluster is assumed, the lensing estimate o f the cluster mass is a factor of 2 higher than that obtained from X-ray ob servations as reported for many distant clusters. However, the elliptical a nd clumpy lens model proposed by Kneib and coworkers is surprisingly consis tent with the X-ray observations, assuming that the X-ray-emitting hot gas is isothermal and in a hydrostatic equilibrium state. The existence of the cooling flow in the central region of the duster is indicated by the short central cooling time and the excess flux detected by ROSAT/HRI compared to the ASCA flux. However, it is shown that, even if the Cl 2236-04 has a cool ing how in the central region, the temperature measured by ASCA, which is t he mean emission-weighted cluster temperature in this case, should not be d ifferent from the virial temperature of the cluster. Therefore, we conclude that the effects of the clumpiness and nonzero ellipticity in the mass dis tribution of the cluster are essential to explain the observed feature of t he giant luminous are, and in this cluster there is no discrepancy between strong lensing and X-ray estimation of the cluster mass.