Hard X-Ray Radiation in the Coma Cluster Spectrum
Hard X-Ray Radiation in the Coma Cluster Spectrum
复制标题
后发星团光谱中的硬 X 射线辐射
DOI：
10.1086/311902
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
A. Santangelo
中科院分区：
文献类型：
--
作者：
R. Fusco;D. Dal Fiume;L. Feretti;G. Giovannini;P. Grandi;G. Matt;S. Molendi;A. Santangelo
BeppoSAX首次在彗星团中探测到硬X射线辐射。由于Phoswich探测系统(PDS)仪器前所未有的灵敏度，已探测到高达~80keV的源。有明显的证据表明(4.5keV)的非热发射超过了~25keV以上的热发射。硬过剩不太可能是出现在PDS视野中的Seyfert 1星系X Comae的结果。由于宇宙微波背景光子上的逆康普顿散射而产生的硬光谱尾巴被预测为具有射电晕的星系团，如彗星。结合射电观测，得到了体积平均磁场约为0.15μG，发射电子的电子能量密度约为7×10−14ergs cm-3。
Hard X-ray radiation has been detected for the first time in the Coma Cluster by BeppoSAX. Thanks to the unprecedented sensitivity of the Phoswich Detection System (PDS) instrument, the source has been detected up to ~80 keV. There is clear evidence (4.5 σ) for nonthermal emission in excess of thermal emission above ~25 keV. The hard excess is very unlikely to be the result of X Comae, the Seyfert 1 galaxy that is present in the field of view of the PDS. A hard spectral tail that is due to inverse Compton scattering on cosmic microwave background photons is predicted in clusters, like Coma, with radio halos. Combining the present results with radio observations, a volume-averaged intracluster magnetic field of ~0.15 μG is derived, while the electron energy density of the emitting electrons is ~7×10−14 ergs cm-3.