We investigate properties of the interstellar medium (ISM) interacting with shocks around the Galactic supernova remnant IC443, using the results of near-infrared [FeII] and H2 line mapping with the IRSF/SIRIUS. In the present study, we newly performed H2 1-0 S(1) and 2-1 S(1) line mapping with the narrow-band filters tuned for these lines, covering the entire remnant (30'x35'). Combined with an [FeII] line map, our result shows that the H2 line emission is significantly detected in the southern region, while the [FeII] line emission is detected all over the remnant, suggesting that slow and fast shocks propagate through the southern region and the entire remnant, respectively. In particular, the H2 line emission is relatively strong compared to the [FeII] line emission in the southwestern region, where TeV gamma-ray emission is detected. As the strong H2 line emission indicates the dominance of the dense ISM, this result supports the scenario that the gamma-ray emission is likely to be produced through a heavy interaction between cosmic-ray protons and the dense ISM in the southwestern shell. We also find that the H2 and [FeII] line emissions show an anti-correlated spatial distribution in the same region, suggesting the presence of the clumpy ISM. Such a clumpy morphology of the ISM around IC443 may assist cosmic-ray protons to efficiently interact with large amounts of the ISM protons.

中文翻译：

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使用 IRSF/SIRIUS 对超新星遗迹 IC 443 的近红外 [${\bf{Fe}}\,{\rm{\small{II}}$] 和 H2 线映射

我们使用 IRSF/SIRIUS 的近红外 [FeII] 和 H2 线映射结果，研究星际介质 (ISM) 与银河系超新星遗迹 IC443 周围的冲击相互作用的特性。在本研究中，我们新执行了 H2 1-0 S(1) 和 2-1 S(1) 线映射，窄带滤波器针对这些线进行了调整，覆盖了整个剩余部分 (30'x35')。结合[FeII]线图，我们的结果表明在南部地区明显检测到H2线发射，而在整个残余物都检测到[FeII]线发射，表明慢速和快速冲击在南部地区传播和整个残余，分别。特别是，与检测到 TeV 伽马射线发射的西南地区的 [FeII] 线发射相比，H2 线发射相对较强。由于强 H2 线发射表明致密 ISM 占主导地位，该结果支持伽马射线发射可能是通过宇宙射线质子与西南壳中致密 ISM 之间的重相互作用产生的假设。我们还发现 H2 和 [FeII] 线发射在同一区域显示出反相关的空间分布，表明存在团块 ISM。IC443 周围 ISM 的这种块状形态可能有助于宇宙射线质子有效地与大量 ISM 质子相互作用。我们还发现 H2 和 [FeII] 线发射在同一区域显示出反相关的空间分布，表明存在团块 ISM。IC443 周围 ISM 的这种块状形态可能有助于宇宙射线质子与大量 ISM 质子有效相互作用。我们还发现 H2 和 [FeII] 线发射在同一区域显示出反相关的空间分布，表明存在团块 ISM。IC443 周围 ISM 的这种块状形态可能有助于宇宙射线质子有效地与大量 ISM 质子相互作用。