论文标题
$ Chandra $和Alma揭示的NGC 2110中Co Gas的AGN X射线辐照
AGN X-ray irradiation of CO gas in NGC 2110 revealed by $Chandra$ and ALMA
论文作者
论文摘要
我们报告了NGC 2110的Fe-K $α$线的空间分布，在NGC 2110中为230.538 GHz（$ j $ = 2--1）行，由$ Chandra $和Alma $ \ $ \ $ \ $ 0.5 ARCSEC揭示。 A $ Chandra $ 6.2---6.5 KEV-3.0--6.0 KEV图像表明，Fe-k $α$排放优先沿西北到西南方向扩展到$ \ sim $ 3 $ 3 ARCSEC或500 pc，在每一侧。空间分辨的光谱分析仅在西北和东南地区找到明显的FE-K $α$排放线来支持这一点。此外，发现它们的等效宽度是$ \ sim $ 1.5 keV，这表明核X射线照射作为物理起源表示荧光。相比之下，CO（$ j $ = 2--1）的排放量很弱。对于定量讨论，我们通过遵循X射线主导区域（XDR）模型来得出电离参数。然后，我们发现它们足够高，可以解释CO和/或H $ _2 $的X射线解离的结果。另一种可能性也是CO分子遵循超热分布，从而在较高$ j $线的情况下更明亮。鼓励进一步的后续观察得出关于主要改变遗嘱间特性的结论，以及X射线辐照是否最终会影响周围的恒星形成作为AGN反馈。
We report spatial distributions of the Fe-K$α$ line at 6.4 keV and the CO($J$ = 2--1) line at 230.538 GHz in NGC 2110, which are respectively revealed by $Chandra$ and ALMA at $\approx$ 0.5 arcsec. A $Chandra$ 6.2--6.5 keV-to-3.0--6.0 keV image suggests that the Fe-K$α$ emission extends preferentially in a northwest-to-southeast direction out to $\sim$ 3 arcsec, or 500 pc, on each side. Spatially-resolved spectral analyses support this by finding significant Fe-K$α$ emission lines only in northwest and southeast regions. Moreover, their equivalent widths are found $\sim$ 1.5 keV, indicative for the fluorescence by nuclear X-ray irradiation as the physical origin. By contrast, CO($J$ = 2--1) emission is weak therein. For quantitative discussion, we derive ionization parameters by following an X-ray dominated region (XDR) model. We then find them high enough to interpret the weakness as the result of X-ray dissociation of CO and/or H$_2$. Another possibility also remains that CO molecules follow a super-thermal distribution, resulting in brighter emission in higher-$J$ lines. Further follow-up observations are encouraged to draw a conclusion on what predominantly changes the inter-stellar matter properties, and whether the X-ray irradiation eventually affects the surrounding star formation as an AGN feedback.
