Chandra measurements of the distribution of mass in the luminous lensing cluster Abell 2390

We present spatially resolved X-ray spectroscopy of the luminous lensing cl uster Abell 2390, using observations made with the Chandra observatory. The temperature of the X-ray gas rises with increasing radius within the centr al similar to 200 kpc of the cluster, and then remains approximately isothe rmal, with kT = 11.5(-1.6)(+1.5) keV, out to the limits of the observations at r similar to1.0 Mpc. The total mass profile determined from the Chandra data has a form in good agreement with the predictions from numerical simu lations. Using the parametrization of Navarro, Frenk and White, we measure a scale radius r(s)similar to0.8 Mpc and a concentration parameter c simila r to3. The best-fitting X-ray mass model is in good agreement with independ ent gravitational lensing results and optical measurements of the galaxy ve locity dispersion in the cluster. The X-ray gas to total mass ratio rises w ith increasing radius with f(gas)similar to 21 per cent at r = 0.9 Mpc. The azimuthally averaged 0.3-7.0 keV surface brightness profile exhibits a sma ll core radius and a clear 'break' at r similar to 500 kpc, where the slope changes from S-X similar to r(-1.5) to S-X similar to r(-3.6). The data fo r the central region of the cluster indicate the presence of a cooling flow with a mass deposition rate of 200-300 M. yr(-1) and an effective age of 2 -3 Gyr.