Temperature and entropy profiles to the virial radius of the Abell 1246 cluster observed with Suzaku

Abstract

We report properties of the intracluster medium (ICM) in Abell 1246 to the virial radius (r200) and further outside as observed with Suzaku. The ICM emission is clearly detected to r200, and we derive profiles of electron temperature, density, entropy, and clustermass based on the spectral analysis. The temperature shows variation from ∼7 keV at the central region to ∼2.5 keV around r200. The total mass in r500 is (4.3 ± 0.4) × 1014 M⊙, assuming hydrostatic equilibrium. At r > r500, the hydrostatic mass starts to decline and we therefore employ the total mass within r200 based on a weak-lens mass profile obtained from a sample of lower-mass clusters. This yields a gasmass fraction at r200 consistent with the cosmic baryon fraction, i.e., ∼17%. The entropy profile indicates a flatter slope than that of the numerical simulation, particularly in r > r500. These tendencies are similar to those of other clusters observed with Suzaku. We detect no significant ICM emission outside of r200, and 2σ upper limits of redshifted O VII and O VIII line intensities are constrained to be less than 2.9 and 5.6 × 10-7 photons cm-2 s-1 arcmin-2, respectively. The O VII line upper limit indicates nH < 4.7 × 10-5 cm-3 (Z/0.2 Z⊙)-1/2 (L/20 Mpc)-1/2, which corresponds to an overdensity, δ < 160 (Z/0.2 Z⊙)-1/2 (L/20 Mpc)-1/2.