R. Lieu et al., DIFFUSE EXTREME-ULTRAVIOLET EMISSION FROM THE COMA CLUSTER - EVIDENCEFOR RAPIDLY COOLING GASES AT SUBMEGAKELVIN TEMPERATURES, Science, 274(5291), 1996, pp. 1335-1338
The central region of the Coma cluster of galaxies was observed in the
energy band from 0.065 to 0.245 kiloelectron volts by the Deep Survey
telescope aboard the Extreme Ultraviolet Explorer. A diffuse emission
halo of angular diameter similar to 30 are minutes was detected. The
extreme-ultraviolet (EUV) emission level exceeds that expected from th
e x-ray temperature gas in Coma. This halo suggests the presence of tw
o more phases in the emitting gas, one at a temperature of similar to
2 x 10(6) kelvin and the other at similar to 8 x 10(5) kelvin. The lat
ter phase cools rapidly and, in steady state, would have produced cold
matter with a mass of similar to 10(14) solar masses within the EUV h
alo. Although a similar EUV enhancement was discovered in the Virgo cl
uster, this detection in Coma applies to a noncooling flow system.