XMM-Newton Observations of the Nuclei of the Radio Galaxies 3C 305, DA 240, and 4C 73.08
XMM-Newton Observations of the Nuclei of the Radio Galaxies 3C 305, DA 240, and 4C 73.08
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DOI：
10.1086/592266
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发表时间：
2008-08
期刊：
影响因子：
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通讯作者：
D. Evans;M. Hardcastle;Julia C. Lee;R. Kraft;D. Worrall;M. Birkinshaw;J. Croston
中科院分区：
文献类型：
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作者：
D. Evans;M. Hardcastle;Julia C. Lee;R. Kraft;D. Worrall;M. Birkinshaw;J. Croston
我们给出了对附近射电星系3C305、DA240和4C73.08的新的XMM-牛顿史诗观测，并研究了它们的核X射线发射的来源。根据之前的工作，这三个源的核在吸积和喷流相关的X射线发射方面似乎有不同的相对贡献。FRII窄线射电星系(NLRG)4C 73.08的X射线谱由一个严重吸收的幂定律和一个源自未分辨喷流的未吸收幂定律的总和模拟而成，该定律被解释为与发光吸积盘和核周遮蔽结构有关。这一行为与其他窄线射电星系是一致的。低激发FR II射电星系DA 240的X射线辐射最好地模拟为未吸收的幂定律，我们将其与秒尺度喷流联系在一起，类似于我们之前研究过的其他低激发源。然而，窄线射电星系3C305的X射线核没有显示出在其他NLRG中发现的被严重吸收的X射线发射的证据。3C305中的核光谱可能本质上是弱谱线，强发射来自扩展区域，表明存在喷流-环境相互作用。我们对3C305的观测表明，这个源与其他弱射电星系有更密切的关系。这种模棱两可的情况可能会延伸到目前被归类为NLRG的其他来源。我们还给出了对DA240热点的XMM-牛顿和VLA观测，认为这是又一次探测到来自低光度热点的X射线同步辐射。
We present new XMM-Newton EPIC observations of the nuclei of the nearby radio galaxies 3C 305, DA 240, and 4C 73.08, and investigate the origin of their nuclear X-ray emission. The nuclei of the three sources appear to have different relative contributions of accretion- and jet-related X-ray emission, as expected based on earlier work. The X-ray spectrum of the FR II narrow-line radio galaxy (NLRG) 4C 73.08 is modeled with the sum of a heavily absorbed power law that we interpret to be associated with a luminous accretion disk and circumnuclear obscuring structure, and an unabsorbed power law that originates in an unresolved jet. This behavior is consistent with other narrow-line radio galaxies. The X-ray emission of the low-excitation FR II radio galaxy DA 240 is best modeled as an unabsorbed power law that we associate with a parsec-scale jet, similar to other low-excitation sources that we have studied previously. However, the X-ray nucleus of the narrow-line radio galaxy 3C 305 shows no evidence for the heavily absorbed X-ray emission that has been found in other NLRGs. It is possible that the nuclear optical spectrum in 3C 305 is intrinsically weak-lined, with the strong emission arising from extended regions that indicate the presence of jet-environment interactions. Our observations of 3C 305 suggest that this source is more closely related to other weak-lined radio galaxies. This ambiguity could extend to other sources currently classified as NLRGs. We also present XMM-Newton and VLA observations of the hot spot of DA 240, arguing that this is another detection of X-ray synchrotron emission from a low-luminosity hot spot.