X-ray total mass estimate for the nearby relaxed cluster A3571

We constrain the total mass distribution in the cluster A3571, combining sp atially resolved ASCA temperature data with ROSAT imaging data with the ass umption that the cluster is in hydrostatic equilibrium. The total mass with in r(500) (1.7 h(50)(-1) Mpc) is M-500 = 7.8(-2.2)(+1.4) x 10(14) h(50)(-1) M-circle dot at 90% confidence, 1.1 times smaller than the isothermal esti mate. The Navarro, Frenk, & White "universal profile" is a good description of the dark matter density distribution in A3571. The gas density profile is shallower than the dark matter profile, scaling as r(-2.1) at large radi i, leading to a monotonically increasing gas mass fraction with radius. Wit hin r(500) the gas mass fraction reaches a value of f(gas) = 0.19(-0.03)(+0 .06) h(50)(-3/2) (90% confidence errors). Assuming that this value off,,, i s a lower limit for the universal value of the baryon fraction, we estimate the 90% confidence upper limit of the cosmological matter density to be Om ega(m) < 0.4.