Interaction between the Supernova Remnant HB 21 and Molecular Clouds
Interaction between the Supernova Remnant HB 21 and Molecular Clouds
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DOI：
10.1086/498232
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发表时间：
2006-01
期刊：
影响因子：
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通讯作者：
D. Byun;B. Koo;K. Tatematsu;K. Sunada
中科院分区：
文献类型：
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作者：
D. Byun;B. Koo;K. Tatematsu;K. Sunada
利用SRAO 6米望远镜对混合形态超新星遗迹HB 21进行了12CO J = 1-0的观测。整个信噪比区域采用全波束网格间距（2’），部分采用半波束间距（1’）。我们在信噪比的北部、西北部和中心发现了具有宽（Δv≥10 km s-1）发射线的激波云。西北方向的大云（~20′）呈弓形形态，沿云边界的射电辐射增强。在残骸的中央，x射线明亮的区域，敏感的CO观测显示了小的宽线云。它们可能是蒸发云的候选者，这可能是中心区域热x射线增强的原因。在北部的v型射电结构中也发现了激波云。我们的研究结果表明，HB 21不寻常的射电特征和中心热x射线增强可能是与分子云相互作用的结果。用NRO 45米望远镜绘制了两个1英尺大小的激波团块的高分辨率映射。对于北部的u形团块，我们发现温度和密度在u形底部附近增加。观测到的特征与理论预测的云被从南向北传播的激波扫过相符。对于南部的另一个震波团，中心速度系统地以11 km s-1 pc-1的梯度变化。考虑到所有可用的距离估计，我们建议1.7公里作为到HB 21的距离。
We have carried out 12CO J = 1-0 observations toward the mixed-morphology supernova remnant (SNR) HB 21 using the SRAO 6 m telescope. The whole area of the SNR was covered using full-beam grid spacing (2') and partly using half-beam spacing (1'). We discovered shocked clouds with broad (Δv ≳ 10 km s-1) emission lines in the north, northwest, and center of the SNR. The large (~20') cloud in the northwest has a bow-shaped morphology and enhanced radio emission along the cloud boundary. Toward the central, X-ray-bright area of the remnant, sensitive CO observations have revealed small broad-line clouds. They are probable candidates for the evaporating clouds, which may be responsible for the enhanced thermal X-rays in the central area. Shocked clouds have also been discovered in the northern V-shaped radio structure. Our results suggest that the unusual radio features and the central thermal X-ray enhancements of HB 21 might be the result of an interaction with molecular clouds. High-resolution mappings of two shocked, 1' sized clumps were made with the NRO 45 m telescope. For the U-shaped clump in the north, we have found that temperature and density increase near the bottom of the U-shape. The observed features coincide with the theoretical expectation for a cloud swept by a shock wave propagating from the south to the north. For the other shocked clump in the south, the central velocity systematically changes with a gradient of 11 km s-1 pc-1. We suggest 1.7 kpc as the distance to HB 21 by considering all available distance estimates.