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arXiv 1705.01547astro-ph.GA
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Arp 220核区的X射线发射

X-ray emission from the nuclear region of Arp 220

Alessandro Paggi, Giuseppina Fabbiano, Guido Risaliti, Junfeng Wang, Margarita Karovska, Martin Elvis, W. Peter Maksym, Jonathan McDowell, Jay Gallagher

备注：
13 pages, 9 figures, accepted for publication on ApJ. arXiv admin note: text overlap with arXiv:1303.2630
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摘要：

我们提出了一个成像和光谱分析的核区域的ULIRG合并Arp 220，使用深\textit{Chandra} -ACIS观测总结\(\sim 300\mbox{ ks}\)。最内层核区域的亚像素分辨率的窄带成像揭示了两个不同的Fe-K发射源，与红外和射电核团一致。这些源由1'（\(\sim 380\) pc）分隔。东核中的X射线发射被延长和拉长，就像毫米射电图像中观察到的盘发射一样，表明该地区星暴占主导地位。我们估计了两个源的铁-钾等效宽度\(\gtrsim 1\) keV，并观测到2-10 keV的光度\(\sim 2\times{10}^{40}\mbox{ erg}\mbox{ s}^{-1}\)（W）和\(\sim 3 \times {10}^{40}\mbox{ erg}\mbox{ s}^{-1}\)（E）。在6-7 keV波段，这些区域的发射主要由6.7 keV的Fe \textsc{xxv}线，这表明碰撞电离气体的贡献。这种气体的热能含量与II型SNe在星际介质中注入的动能一致。然而，来自隐藏活动星系核（\(\varv\sim 2000 \mbox{ km}\mbox{ s}^{-1}\)）的核风不能被排除。核区中性Fe-K \(α\)通量的\(3σ\)上限对应于活动星系核2-10 keV的本征光度\(< 1\times {10}^{42}\mbox{ erg}\mbox{ s}^{-1}\)（W）和\(< 0.4\times {10}^{42}\mbox{ erg}\mbox{ s}^{-1}\)（E）。对于典型的活动星系核SED，辐射热光度分别为\(< 3\times {10}^{43}\mbox{ erg}\mbox{ s}^{-1}\)（W）和\(< 8\times {10}^{43}\mbox{ erg}\mbox{ s}^{-1}\)（E），对于标准效率为10%的爱丁顿有限活动星系核，辐射热光度分别为\(<1\times{10}^5 M_{\astrosun}\)（W）和\(< 5\times{10}^5 M_{\astrosun}\)（E）。

英文摘要：

We present an imaging and spectral analysis of the nuclear region of the ULIRG merger Arp 220, using deep \textit{Chandra}-ACIS observations summing up to \(\sim 300\mbox{ ks}\). Narrow-band imaging with sub-pixel resolution of the innermost nuclear region reveals two distinct Fe-K emitting sources, coincident with the infrared and radio nuclear clusters. These sources are separated by 1' (\(\sim 380\) pc). The X-ray emission is extended and elongated in the eastern nucleus, like the disk emission observed in millimeter radio images, suggesting starburst dominance in this region. We estimate Fe-K equivalent width \(\gtrsim 1\) keV for both sources, and observed 2-10 keV luminosities \(\sim 2\times{10}^{40}\mbox{ erg}\mbox{ s}^{-1}\) (W) and \(\sim 3 \times {10}^{40}\mbox{ erg}\mbox{ s}^{-1}\) (E). In the 6-7 keV band the emission from these regions is dominated by the 6.7 keV Fe \textsc{xxv} line, suggesting contribution from collisionally ionized gas. The thermal energy content of this gas is consistent with kinetic energy injection in the interstellar medium by Type II SNe. However, nuclear winds from hidden AGN (\(\varv\sim 2000 \mbox{ km}\mbox{ s}^{-1}\)) cannot be excluded. The \(3σ\) upper limits on the neutral Fe-K\(α\) flux of the nuclear regions correspond to intrinsic AGN 2-10 keV luminosities \(< 1\times {10}^{42}\mbox{ erg}\mbox{ s}^{-1}\) (W) and \(< 0.4\times {10}^{42}\mbox{ erg}\mbox{ s}^{-1}\) (E). For typical AGN SEDs the bolometric luminosities are \(< 3\times {10}^{43}\mbox{ erg}\mbox{ s}^{-1}\) (W) and \(< 8\times {10}^{43}\mbox{ erg}\mbox{ s}^{-1}\) (E), and black hole masses \(<1\times{10}^5 M_{\astrosun}\) (W) and \(< 5\times{10}^5 M_{\astrosun}\) (E) for Eddington limited AGNs with a standard 10\% efficiency.

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