Temperature and Entropy Profiles to the Virial Radius of Abell 1246 Cluster Observed with Suzaku

Abstract

We report properties of the intracluster medium (ICM) in Abell~1246 to the virial radius ($r_{200}$) and further outside as observed with Suzaku. The ICM emission is clearly detected to $r_{200}$, and we derive profiles of electron temperature, density, entropy, and cluster mass based on the spectral analysis. The temperature shows variation from $\sim 7$ keV at the central region to $\sim 2.5$ keV around $r_{200}$. The total mass in $r_{500}$ is $(4.3\pm 0.4)\times 10^{14}{M}_{\odot }$, assuming hydrostatic equilibrium. At $r>r_{500}$, the hydrostatic mass starts to decline and we, therefore, employ the total mass within $r_{200}$ based on weak-lens mass profile obtained from a sample of lower mass clusters. This yields the gas mass fraction at $r_{200}$ consistent with the cosmic baryon fraction, i.e. $\sim 17$%. The entropy profile indicates a flatter slope than that of the numerical simulation, particularly in $r>r_{500}$. These tendencies are similar to those of other clusters observed with Suzaku. We detect no significant ICM emission outside of $r_{200}$, and $2\ddot{I}ƒ$ upper limits of redshifted OVII and OVIII line intensities are constrained to be less than 2.9 and $5.6\times 10^{-7}$ photons cm${}^{-2}$ s${}^{-1}$ arcmin${}^{-2}$, respectively. The OVII line upper limit indicates $n_{\mathrm{H}}<4.7\times 10^{-5}$ cm${}^{-3}$ ($Z/0.2Z_{\odot }$)${}^{-1/2}$ ($L/20\mathrm{Mpc}$)${}^{-1/2}$, which corresponds to an overdensity, $\hat{I}´<160$ ($Z/0.2Z_{\odot }$)${}^{-1/2}$ ($L/20\mathrm{Mpc}$)${}^{-1/2}$.

14 pages, 7 figures, PASJ in press