AN ASCA-ROSAT STUDY OF THE DISTANT, LENSING CLUSTER A-2390

We present the results of a combined study of ASCA and ROSAT observati ons of the distant cluster Abell 2390. For this cluster gravitational arc as well as weak lensing shear have been previously discovered. We determine the surface brightness profile and the gas density distribut ion of the cluster from the ROSAT PSPC and HRI data. A combined spatia lly resolved spectral analysis of the ASCA and ROSAT data show that th e temperature distribution of the intracluster medium of A 2390 is con sistent with an isothermal temperature distribution in the range 9 to 12 keV except for the central region. Within a radius of 160h(50)(-1) kpc the cooling time is found to be shorter than the Hubble time, impl ying the presence of a cooling flow. In this central region we find st rong evidence for a multi-temperature structure. Detailed analysis of the combined ASCA and ROSAT data yields a self-consistent result for t he spectral structure and the surface brightness profile of the cluste r with a cooling flow of about 500 - 700 Mo. y(-1) and an age of about 10(10) y. From the constraints on the temperature and density profile of the intracluster gas we determine the gravitational mass profile o f the cluster and find a mass of about 2 . 10(15) M. within a radius o f 3h(50)(-1) Mpc. A comparison of the projected mass profiles of the c luster shows an excellent agreement between the mass determined from X -ray data and the mass determined from the models for the gravitationa l are and the weak lensing results. This agreement in this object, as compared to other cases where a larger lensing mass was implied, may p robably be due to the fact that A 2390 is more relaxed than most other cases for which gravitational lensing mass and X-ray mass have been c ompared so far.