论文标题
h $ _2 $在行星NEBULAE NGC 7009和NGC 6543的低离世结构中排放
H$_2$ emission in the low-ionisation structures of the Planetary Nebulae NGC 7009 and NGC 6543
论文作者
论文摘要
尽管在过去几十年中进行了许多研究，但行星星云（PNE）的低离世结构（LIS）仍然存在几个谜。最近的成像调查表明，LIS由分子气体组成。在这里，我们报告了NGC 7009和NGC 6543的H $ _2 $通过非常深的狭窄带h $ _2 $图像与Niri@gemini拍摄的图像。 H2 1-0 s（1）线的表面亮度估计为（0.46-2.9）$ \ times $ 10 $^{ - 4} $ erg s $^{ - 1} $ cm $^{ - 2} $ sr $^{ - 1} s $^{ - 1} $ cm $^{ - 2} $ sr $^{ - 1} $在NGC 6543中，信噪比分别为10-42和3-4。这些发现提供了对LISS中隐藏的H $ _2 $气体的进一步确认。根据最近提出的诊断图R（h $ _2 $）= H $ _2 $ _2 $ _2 $ _2 $ 1-0 s（1）/h $ _2 $ _2 $ 2-1 S（1）对R（Br $γ$）= H $ _2 $ _2 $ _2 $ 1-0 s（1）/BR $γ$，建议对机械责任追踪H $ h $ _2 $ _2。将我们的观察结果与冲击和紫外线（UV）分子激发模型以及文献汇编的许多观察结果进行比较，表明我们不能以紫外线或冲击为分子发射的机制得出结论。
Despite the many studies in the last decades, the low-ionisation structures (LISs) of planetary nebulae (PNe) still hold several mysteries. Recent imaging surveys have demonstrated that LISs are composed of molecular gas. Here we report H$_2$ emission in the LISs of NGC 7009 and NGC 6543 by means of very deep narrow-band H$_2$ images taken with NIRI@Gemini. The surface brightness of the H2 1-0 S(1) line is estimated to be (0.46-2.9)$\times$10$^{-4}$ erg s$^{-1}$ cm$^{-2}$ sr$^{-1}$ in NGC 7009 and (0.29-0.48)$\times$10$^{-4}$ erg s$^{-1}$ cm$^{-2}$ sr$^{-1}$ in NGC 6543, with signal-to-noise ratios of 10-42 and 3-4, respectively. These findings provide further confirmation of hidden H$_2$ gas in LISs. The emission is discussed in terms of the recent proposed diagnostic diagram R(H$_2$)=H$_2$ 1-0 S(1)/H$_2$ 2-1 S(1) versus R(Br$γ$)=H$_2$ 1-0 S(1)/Br$γ$, which was suggested to trace the mechanism responsible for the H$_2$ excitation. Comparing our observations to shock and ultraviolet (UV) molecular excitation models, as well as a number of observations compiled from the literature showed that we cannot conclude for either UV or shocks as the mechanism behind the molecular emission.
