MOLECULAR CLUMPS AND INFRARED CLUSTERS IN THE S247, S252, AND BFS52 REGIONS
MOLECULAR CLUMPS AND INFRARED CLUSTERS IN THE S247, S252, AND BFS52 REGIONS
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DOI：
10.1088/0004-637x/768/1/72
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发表时间：
2013-04
期刊：
影响因子：
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通讯作者：
T. Shimoikura;K. Dobashi;H. Saito;Tomoaki Matsumoto;F. Nakamura;A. Nishimura;K. Kimura;T. Onishi;H. Ogawa
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文献类型：
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作者：
T. Shimoikura;K. Dobashi;H. Saito;Tomoaki Matsumoto;F. Nakamura;A. Nishimura;K. Kimura;T. Onishi;H. Ogawa
我们目前的观测结果对S247，S252和BFS 52 H ii区域与各种分子线使用1.85米射电望远镜和45米望远镜在野边山射电天文台。在观测区域内至少有11个年轻的红外星团（IR cluster）。我们发现~（12）CO（J = 2-1）有两个速度分量，它们的空间分布呈反相关。红外线团位于它们的界面上，这表明两个不同的云以不同的速度相互碰撞，这可能导致了团的形成。根据13 CO（J = 1-0）和C18 O（J = 1-0）的观测结果，我们在三个H ii区及其周围识别出16个团簇。其中11个星团与红外星团有关，另外5个星团与任何已知的年轻恒星天体无关。我们研究了16个团块的速度分散的变化，作为从集群或团块的中心的距离的函数。具有集群的集群往往具有随着距集群中心的距离而增加的速度分散，而没有集群的集群在集群范围内显示出平坦的速度分散。一个12 CO流出已被发现在一些团块与IR集群，但不是在其他团块，支持这些团块的强大关系到更广泛的速度分散区。我们还估计了一个平均星星的形成效率为30%左右的团块与IR集群在三个H ii区域。
We present results of the observations carried out toward the S247, S252, and BFS52 H ii regions with various molecular lines using the 1.85 m radio telescope and the 45 m telescope at Nobeyama Radio Observatory. There are at least 11 young infrared clusters (IR clusters) within the observed region. We found that there are two velocity components in 12CO (J = 2–1), and also that their spatial distributions show an anti-correlation. The IR clusters are located at their interfaces, suggesting that two distinct clouds with different velocities are colliding with each other, which may have induced the cluster formation. Based on 13CO (J = 1–0) and C18O (J = 1–0) observations, we identified 16 clumps in and around the three H ii regions. Eleven of the clumps are associated with the IR clusters and the other five clumps are not associated with any known young stellar objects. We investigated variations in the velocity dispersions of the 16 clumps as a function of the distance from the center of the clusters or the clumps. Clumps with clusters tend to have velocity dispersions that increase with distance from the cluster center, while clumps without clusters show a flat velocity dispersion over the clump extents. A 12CO outflow has been found in some of the clumps with IR clusters but not in the other clumps, supporting a strong relation of these clumps to the broader velocity dispersion region. We also estimated a mean star formation efficiency of ∼30% for the clumps with IR clusters in the three H ii regions.