Back to the Abstracts Index Page
R. Lieu, J.P.D. Mittaz, S. Bowyer (1), J.O. Breen, F.J. Lockman, E.M. Murphy, and C.-Y. Hwang
1) Center for EUV Astrophysics, 2150 Kittredge Street, University
of California, Berkeley, CA 94720
The central region of the Coma cluster of galaxies was observed in the 0.065 - 0.245 keV energy band by the deep survey (DS) telescope aboard the Extreme Ultraviolet Explorer (EUVE). A diffuse emission halo of angular diameter ~30 arcmin was detected. The EUV emission level significantly exceeds that expected from the well-measured X-ray temperature gas in Coma. Similar "soft excesses" are also evident in the Roentgen Satellite (ROSAT) Position Sensitive Proportional Counter (PSPC) data. The phenomenon cannot be explained by an arbitrary reduction of the Galactic H and He column densities. Rather, it suggest the presence of two more phases in the emitting gas, one at a temperature of ~2E+06 K and the other ~8E+05 K. The latter cools rapidly and, in steady state, would have produced cold matter of mass ~1E+14 solar masses (M_solar) within the EUV halo. Although a similar EUV enhancement was discovered in the Virgo cluster, this is the first detection of its presence in a non-cooling flow system.
Back to the Abstracts Index Page
