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A Giant Warm Baryonic Halo for the Coma Cluster
- Publication Year :
- 2002
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 2002.
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Abstract
- Several deep PSPC observations of the Coma cluster unveil a very large-scale halo of soft X-ray emission, substantially in excess of the well know radiation from the hot intra-cluster medium. The excess emission, previously reported in the central cluster regions through lower-sensitivity EUVE and ROSAT data, is now evident out to a radius of 2.5 Mpc, demonstrating that the soft excess radiation from clusters is a phenomenon of cosmological significance. The spectrum at these large radii cannot be modeled non-thermally, but is consistent with the original scenario of thermal emission at warm temperatures. The mass of this plasma is at least on par with that of the hot X-ray emitting plasma, and significantly more massive if the plasma resides in low-density filamentary structures. Thus the data lend vital support to current theories of cosmic evolution, which predict greater than 50 percent by mass of today's baryons reside in warm-hot filaments converging at clusters of galaxies.
- Subjects :
- Astronomy
Subjects
Details
- Language :
- English
- Database :
- NASA Technical Reports
- Publication Type :
- Report
- Accession number :
- edsnas.20030002476
- Document Type :
- Report