Photon dominated regions in NGC 3603 - [CI] and mid-J CO line emission
Photon dominated regions in NGC 3603 - [CI] and mid-J CO line emission
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DOI：
10.1051/0004-6361/201014765
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发表时间：
2010-11
影响因子：
6.5
通讯作者：
M. Röllig;M. Hitschfeld;D. Rabanus;U. Graf;M. Cubick;M. Fujishita;J. May;N. Mizuno;Y. Yonekura;K. Jacobs;Manuel Aravena;M. Miller;L. Bronfman;F. Bensch;Uli Klein;T. Onishi;F. Bertoldi;H. Sasago;H. Yamamoto;C. Kramer;N. Honingh;T. Minamidani;J. Stutzki;Y. Fukui;J. Pineda;C. Rajbahak;K. Sun;Yosuke Miyamoto;R. Schieder;B. Koo;Shingo Ito;R. Simon;Y. Park;V. Ossenkopf;H. Jakob
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文献类型：
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作者：
M. Röllig;M. Hitschfeld;D. Rabanus;U. Graf;M. Cubick;M. Fujishita;J. May;N. Mizuno;Y. Yonekura;K. Jacobs;Manuel Aravena;M. Miller;L. Bronfman;F. Bensch;Uli Klein;T. Onishi;F. Bertoldi;H. Sasago;H. Yamamoto;C. Kramer;N. Honingh;T. Minamidani;J. Stutzki;Y. Fukui;J. Pineda;C. Rajbahak;K. Sun;Yosuke Miyamoto;R. Schieder;B. Koo;Shingo Ito;R. Simon;Y. Park;V. Ossenkopf;H. Jakob
目标。我们的目标是推导出星际气体的激发条件以及NGC 3603周围分子云中的局部FUV强度，以获得气体如何被中心恒星激发的相干图像。方法. NANTEN 2 -4 m亚毫米波天线用于绘制年轻OB星团NGC 3603 YC周围2' x 2'区域内的[CI] 1-0、2-1和CO 4-3、7-6谱线。这些数据与C（18）O 2-1数据，HIRES处理的IRAS 60 μ m和100 μ m的FIR连续图，和斯皮策/IRAC地图相结合。结果NANTEN 2的观测结果表明，在星团的东南和西南方向存在两个分子团，并证实了之前的CS和C（18）O观测已经发现的整体结构。我们发现CO和[CI]的峰强度的轻微位置偏移，并且原子碳似乎与分子材料相比进一步延伸。我们使用的HIRES远红外尘埃数据，得出一个地图的FUV场加热尘埃。我们将FUV场约束为chi = 3-6 x 10（3）的值，单位为云上的Draine场。大约0.2%至0.3%的总FUV能量在ISO观察到的[CII] 158 μ m冷却线中重新发射。应用LTE和逃逸概率计算，我们推导出温度（T（MM 1）= 43 K，T（MM 2）= 47 K），柱密度（N（MM 1）= 0.9 x 10（22）cm（-2），N（MM 2）= 2.5 x 10（22）cm（-2））和密度（n（MM 1）= 3 x 10（3）cm（-3），n（MM 2）= 10（3）- 10（4）cm（-3））。结论.星团与周围的分子云强烈地相互作用，控制着它的结构和物理条件。稳定性分析表明存在着引力坍缩的气体团，这些气体团应该会导致星星的形成。在分子云的外围已经观察到了嵌入式红外光源，这似乎支持了我们的结论。
Aims. We aim at deriving the excitation conditions of the interstellar gas as well as the local FUV intensities in the molecular cloud surrounding NGC 3603 to get a coherent picture of how the gas is energized by the central stars. Methods. The NANTEN2-4 m submillimeter antenna is used to map the [CI] 1-0, 2-1 and CO 4-3, 7-6 lines in a 2' x 2' region around the young OB cluster NGC 3603 YC. These data are combined with C(18)O 2-1 data, HIRES-processed IRAS 60 mu m and 100 mu m maps of the FIR continuum, and Spitzer/IRAC maps. Results. The NANTEN2 observations show the presence of two molecular clumps located south-east and south-west of the cluster and confirm the overall structure already found by previous CS and C(18)O observations. We find a slight position offset of the peak intensity of CO and [CI], and the atomic carbon appears to be further extended compared to the molecular material. We used the HIRES far-infrared dust data to derive a map of the FUV field heating the dust. We constrain the FUV field to values of chi = 3-6 x 10(3) in units of the Draine field across the clouds. Approximately 0.2 to 0.3% of the total FUV energy is re-emitted in the [CII] 158 mu m cooling line observed by ISO. Applying LTE and escape probability calculations, we derive temperatures (T(MM1) = 43 K, T(MM2) = 47 K), column densities (N(MM1) = 0.9 x 10(22) cm(-2), N(MM2) = 2.5 x 10(22) cm(-2)) and densities (n(MM1) = 3 x 10(3) cm(-3), n(MM2) = 10(3) - 10(4) cm(-3)) for the two observed molecular clumps MM1 and MM2. Conclusions. The cluster is strongly interacting with the ambient molecular cloud, governing its structure and physical conditions. A stability analysis shows the existence of gravitationally collapsing gas clumps which should lead to star formation. Embedded IR sources have already been observed in the outskirts of the molecular cloud and seem to support our conclusions.