An X‐Ray Temperature Map of Abell 1795, a Galaxy Cluster in Hydrostatic Equilibrium

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Abstract
We present the first two-dimensional X-ray temperature map of the galaxy cluster Abell 1795, which harbors a strong cooling flow. We also present an X-ray surface brightness map of the cluster. The temperature map clearly shows a cool region coincident with the peak X-ray surface brightness and with the cD galaxy. Outside this region, there is no significant temperature structure. The X-ray isophotes are slightly elliptical but very smooth, with a small asymmetry to the north, coincident with a region of enhanced galaxy density. All these observations are consistent with an evolutionary scenario in which clusters without recent mergers have had enough time for the bulk of the cluster to equilibrate, becoming isothermal except for the centers which develop cooling flows. Since A1795 is likely to be nearly spherically symmetric and in hydrostatic equilibrium, it should be possible to estimate the total mass and gas mass fraction relatively free of systematic errors. Within a radius of 0.5 h−1 Mpc, the radius to which we have temperature measurements, the total mass is 2.7 ± 0.22 × 1014 h−1 M☉ , of which the gas contributes 4.6 ± 0.9 h−1.5 percent. We do not confirm the high value of excess absorbing material in the cooling flow region found previously using other instruments.

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