The XMM-Newton Examination of Energetics in the East Lobe of the Nearby Radio Galaxy Fornax A (NGC 1316)
The XMM-Newton Examination of Energetics in the East Lobe of the Nearby Radio Galaxy Fornax A (NGC 1316)
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附近射电星系 Fornax A (NGC 1316) 东叶的 XMM-牛顿能量学检验
DOI：
10.1086/504253
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
H. Kaneda
中科院分区：
文献类型：
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作者：
N. Isobe;K. Makishima;M. Tashiro;K. Itoh;N. Iyomoto;I. Takahashi;H. Kaneda
报道了对附近射电星系 Fornax A 东射电波瓣的 XMM-Newton 观测。与东叶相关的漫射硬 X 射线发射最初由 ASCA 和 ROSAT 发现，在严格去除 MOS 视场内检测到的 59 个源后，通过重要的信号统计数据证实了这一点。其 X 射线光谱由单一幂律模型描述，该模型被柱密度与物体方向一致的介质吸收。最佳拟合 X 射线光子指数 ГX = 1.62，与根据 29.9 MHz 至 5 GHz 之间的射电频谱确定的同步加速器射电指数 ГR = 1.68 ± 0.1 一致。因此，漫射 X 射线的逆康普顿解释是合理的。东叶的 X 射线通量密度在 1 keV 下测得为 90 ± 21 nJy（包括统计误差和系统误差），指数固定为射电值。这使得电子和磁能密度分别为 3.0 × 10-13 和 6.1 × 10-14 ergs cm-3。后者对应的磁场强度为1.24 μG，小于最小能量条件下估计的磁场强度1.55 μG，但误差稍大。还对西叶的 ASCA 结果进行了重新评估，以表明两个叶在能量方面具有相似的物理条件。
An XMM-Newton observation of the east radio lobe of the nearby radio galaxy Fornax A is reported. The diffuse hard X-ray emission associated with the east lobe, which was initially discovered by ASCA and ROSAT, is confirmed with significant signal statistics, after strictly removing 59 sources detected within the MOS field of view. Its X-ray spectrum is described by a single power-law model, which is absorbed by a medium with a column density consistent with that toward the object. The best-fit X-ray photon index, ΓX = 1.62, agrees with the synchrotron radio index, ΓR = 1.68 ± 0.1, determined from the radio spectrum between 29.9 MHz and 5 GHz. Hence, the inverse Compton interpretation for the diffuse X-rays is justified. The X-ray flux density in the east lobe is measured to be 90 ± 21 nJy at 1 keV (including both statistical and systematic errors) with the index fixed at the radio value. This gives electron and magnetic energy densities of 3.0 × 10-13 and 6.1 × 10-14 ergs cm-3, respectively. The latter corresponds to a magnetic field strength of 1.24 μG, which is smaller than the field estimated under the minimum energy condition, 1.55 μG, although with a slightly large error. Reevaluation is also made of the ASCA result on the west lobe, to show that both lobes share a similar physical condition in terms of energetics.
M.Tashiro：“射电星系 NGC 1316 (Fornax A) 西叶场和粒子能量分布的 X 射线测量”Astrophys.J.Lett.. 546. L19 (2001)
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