The Suzaku Observation of the Nucleus of the Radio-loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material
The Suzaku Observation of the Nucleus of the Radio-loud Active Galaxy Centaurus A: Constraints on Abundances of the Accreting Material
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DOI：
10.1086/519271
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发表时间：
2007-04
期刊：
影响因子：
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通讯作者：
A. Markowitz;T. Takahashi;S. Watanabe;K. Nakazawa;Y. Fukazawa;M. Kokubun;K. Makishima;H. Awaki
中科院分区：
文献类型：
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作者：
A. Markowitz;T. Takahashi;S. Watanabe;K. Nakazawa;Y. Fukazawa;M. Kokubun;K. Makishima;H. Awaki
2005年，朱雀号观测到活动星系核半人马座A的射电噪声，产生了一个宽频带的光谱，范围为0.3-250 keV。筛选后的净曝光时间为每个X射线成像光谱仪（XIS）相机70 ks，硬X射线探测器（HXD）PIN为60.8 ks，HXD GSO为17.1 ks。硬X射线分别由1.5和7 × 1023 cm-2柱吸收的两个相同斜率的幂律拟合。光谱是一致的，与以前的建议，幂律组件是X射线发射subparsec VLBI喷气和邦迪吸积的核心，但它也是一致的部分覆盖的解释。软带主要由扩散等离子体的热发射，并适合由两个温度VAPEC模型，加上第三次幂律分量占散射核发射，喷射发射，并从X射线双星和其他点源的发射。检测到来自Fe、Si、S、Ar、Ca和Ni的窄荧光发射线。Fe Kα谱线宽度给出了黑洞到谱线发射气体距离的200 lt-day下限。Fe，Ca和S K壳层吸收边检测。元素丰度通过荧光和扩散等离子体发射线的吸收边深度和强度来约束。环核物质的高金属丰度（[Fe/H] = +0.1）表明，它不可能起源于相对贫金属的外晕，除非发生了局部星星形成的富集。相对丰度与II型和Ia型超新星的富集相一致。
A Suzaku observation of the nucleus of the radio-loud AGN Centaurus A in 2005 has yielded a broadband spectrum spanning 0.3-250 keV. The net exposure times after screening were 70 ks per X-ray Imaging Spectrometer (XIS) camera, 60.8 ks for the Hard X-ray Detector (HXD) PIN, and 17.1 ks for the HXD GSO. The hard X-rays are fit by two power laws of the same slope, absorbed by columns of 1.5 and 7 × 1023 cm-2, respectively. The spectrum is consistent with previous suggestions that the power-law components are X-ray emission from the subparsec VLBI jet and from Bondi accretion at the core, but it is also consistent with a partial-covering interpretation. The soft band is dominated by thermal emission from the diffuse plasma and is fit well by a two-temperature VAPEC model, plus a third power-law component to account for scattered nuclear emission, jet emission, and emission from X-ray binaries and other point sources. Narrow fluorescent emission lines from Fe, Si, S, Ar, Ca, and Ni are detected. The Fe Kα line width yields a 200 lt-day lower limit on the distance from the black hole to the line-emitting gas. Fe, Ca, and S K-shell absorption edges are detected. Elemental abundances are constrained via absorption edge depths and strengths of the fluorescent and diffuse plasma emission lines. The high metallicity ([Fe/H] = +0.1) of the circumnuclear material suggests that it could not have originated in the relatively metal-poor outer halo unless enrichment by local star formation has occurred. Relative abundances are consistent with enrichment from Type II and Ia supernovae.