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arXiv · astro-ph/0211439

A massive warm baryonic halo in the Coma cluster

M. Bonamente·M. K. Joy·R. Lieu
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Abstract

Several deep PSPC observations of the Coma cluster reveal a very large-scale halo of soft X-ray emission, substantially in excess of the well known radiation from the hot intra-cluster medium. The excess emission, previously reported in the central region of the cluster using lower-sensitivity EUVE and ROSAT data, is now evident out to a radius of 2.6 Mpc, demonstrating that the soft excess radiation from clusters is a phenomenon of cosmological significance. The X-ray spectrum at these large radii cannot be modeled non-thermally, but is consistent with the original scenario of thermal emission from warm gas at ~ 10^6 K. The mass of the warm gas is on par with that of the hot X-ray emitting plasma, and significantly more massive if the warm gas resides in low-density filamentary structures. Thus the data lend vital support to current theories of cosmic evolution, which predict that at low redshift \~30-40 % of the baryons reside in warm filaments converging at clusters of galaxies.

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M. Bonamente, M. K. Joy, R. Lieu. 2002-11-20. A massive warm baryonic halo in the Coma cluster. https://doi.org/10.1086/346220

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