A Massive Warm Baryonic Halo in the Coma Cluster
A Massive Warm Baryonic Halo in the Coma Cluster
复制标题
后发星团中巨大的温暖重子晕
DOI：
10.1086/346220
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
R. Lieu
中科院分区：
文献类型：
--
作者：
M. Bonamente;M. Joy;R. Lieu
对后发星团的几次深度 PSPC 观测揭示了一个非常大范围的软 X 射线发射晕，大大超过了众所周知的热星团内介质的辐射。先前使用较低灵敏度的极紫外探测器 (EUVE) 和 ROSAT 数据在星团中心区域报告的过量发射，现在在半径 2.6 Mpc 范围内很明显，表明来自星团的软过量辐射是一种具有宇宙学意义的现象。这些大半径处的 X 射线光谱无法进行非热建模，但与约 106 K 温热气体热发射的原始情况一致。温热气体的质量与热 X 射线发射等离子体的质量相当，如果温热气体驻留在低密度丝状结构中，则质量明显更大。因此，这些数据为当前的宇宙演化理论提供了重要支持，该理论预测，在低红移下，约 30%-40% 的重子存在于汇聚在星系团中的温暖细丝中。
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 intracluster medium. The excess emission, previously reported in the central region of the cluster using lower sensitivity Extreme Ultraviolet Explorer (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 nonthermally but is consistent with the original scenario of thermal emission from warm gas at ~106 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.