标题： 13CO（J=1-0）对巨HII区NGC 604的实时映射：由于顺序恒星形成导致的分子气体密度和温度的变化 显示英文标题

标题： 13CO(J=1-0) On-the-fly Mapping of the Giant HII Region NGC 604: Variation in Molecular Gas Density and Temperature due to Sequential Star Formation

摘要： 我们使用那须山45米望远镜对螺旋星系M 33中的巨大HII区域NGC 604进行了13CO(J=1-0)线发射观测。 我们在标记为GMC-A、B和C的3个主要巨分子云中检测到了13CO(J=1-0)线发射，这些云从北部开始。 我们在角分辨率为25"（100 pc）的情况下，为每个GMC推导了两条线强度比，即13CO(J=1-0)/12CO(J=1-0)，R13/12，以及12CO(J=3-2)/12CO(J=1-0)，R31。 GMC-A整体的R13/12和R31平均值分别为0.06和0.31，GMC-B整体的R13/12和R31平均值分别为0.11和0.67，GMC-C整体的R13/12和R31平均值分别为0.05和0.36。 此外，我们在GMC-B的12CO(J=1-0)峰值位置得到了R13/12=0.09\pm 0.02和R31=0.76\pm 0.06。 在大速度梯度近似下，我们在GMC-B的12CO(J=1-0)峰值位置确定了气体密度为2.8\times 10^3 cm^-3和动能温度为33+9-5 K。 此外，我们确定了GMC-B整体的平均值为2.5\times 10^3 cm^-3和25\pm 2 K。 我们得出结论，由于不仅在GMC的峰值位置，而且在整个GMC的平均气体密度都超过了10^3 cm^-3，因此在GMC-B中到处形成了致密的分子气体。 另一方面，整个GM-B的动能温度平均值为25 K，明显低于峰值位置的33 K。这是因为HII区域偏向于GMC-B的北部，因此OB恒星只能加热这个GMC的北部，包括12CO(J=1-0)的峰值位置。 显示英文摘要

摘要： We present 13CO(J=1-0) line emission observations with the Nobeyama 45-m telescope toward the giant HII region NGC 604 in the spiral galaxy M 33. We detected 13CO(J=1-0) line emission in 3 major giant molecular clouds (GMCs) labeled as GMC-A, B, and C beginning at the north. We derived two line intensity ratios, 13CO(J=1-0)/12CO(J =1-0), R13/12, and 12CO(J=3-2)/12CO(J =1-0), R31, for each GMC at an angular resolution of 25" (100 pc). Averaged values of R13/12 and R31 are 0.06 and 0.31 within the whole GMC-A, 0.11 and 0.67 within the whole GMC-B, and 0.05 and 0.36 within the whole GMC-C, respectively. In addition, we obtained R13/12=0.09\pm0.02 and R31=0.76\pm0.06 at the 12CO(J=1-0) peak position of the GMC-B. Under the Large Velocity Gradient approximation, we determined gas density of 2.8 \times10^3 cm^-3 and kinetic temperature of 33+9-5 K at the 12CO(J=1-0) peak position of the GMC-B. Moreover, we determined 2.5 \times10^3 cm^-3 and 25\pm2 K as averaged values within the whole GMC-B. We concluded that dense molecular gas is formed everywhere in the GMC-B because derived gas density not only at the peak position of the GMC but also averaged over the whole GMC exceeds 10^3 cm^-3. On the other hand, kinetic temperature averaged over the whole GM-B, 25 K, is significantly lower than that at the peak position, 33 K. This is because HII regions are lopsided to the northern part of the GMC-B, thus OB stars can heat only the northern part, including the 12CO(J=1-0) peak position, of this GMC.