A2163 - An exceptionally hot cluster of galaxies
The X-ray spectrum of the distant galaxy cluster A2163 was measured in the energy range 1-18 keV with the Ginga satellite. A combined analysis of these data with data previously obtained with the Einstein Observatory is presented. The mean temperature and X-ray luminosity derived are exceptionally high compared to other clusters: kT = 12.9 keV, L(x) (2-10 keV) = 3.5 x 10 exp 45 ergs/s for z = 0.15, as are the gas mass (6.7 x 10 exp 14 solar mass) and binding mass (25 x 10 exp 14 solar mass). The very existence of such a cluster can provide interesting constraints on the relative distribution of 'visible' mass and dark matter, an important parameter in cold dark matter models for formation of structure in the universe.
Arnaud, M.↗