The molecular environment of NGC 3603. I. Spatial distribution and kinematic structure
The molecular environment of NGC 3603. I. Spatial distribution and kinematic structure
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NGC 3603的分子环境 一、空间分布和运动结构
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
H. Zinnecker
中科院分区：
文献类型：
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作者：
D. Nürnberger;L. Bronfman;H. Yorke;H. Zinnecker
我们目前的CS（2-1）和CS（3-2）的分子气体的观测与银河系恒星暴模板NGC 3603，在5。� 8 ×16。7，以OB集群为中心。总速度积分图和通道图提供了星暴星系团起源的巨大分子云中稠密气体的空间分布和运动学结构。我们确定了13个半径小于0.8pc的分子团簇，并推导出它们的维里质量上限和H2柱密度下限：M vir（0.4 ±0.2）× 1023 cm −2。其中一个团块，MM 11，明显突出，质量和柱密度比平均水平高4倍。CS（3-2）/CS（2-1）图显示OB星团南部的强度比北部高（0.80 ± 0.08比0.32 ± 0.11），这表明分子气体的物理条件（不透明度或激发温度）有很大的差异。根据平均线峰值速度14.2 ±1.6kms −1，我们推断NGC 3603的运动学距离为7.7 ±0.2kpc。我们估计了NGC 3603 H区中心部分的星星形成效率（>30%）。如果我们假设OB星团的年龄小于300万年，而星星的形成速率大于1.3 ×10 − 300万年−1，则导出的气体去除时间尺度（τ = 600万年）可以解释为什么星爆星团本身几乎没有星际物质。残留的星团MM 1似乎构成了一个突出的支柱的头部，仍然被来自星团大质量恒星的电离辐射和恒星风分散。由于一些分子团簇与近、中红外源以及OH、H2 O和CH 3OH脉泽源有关，我们得出结论，NGC 3603内的星星形成仍在进行。
We present CS(2-1) and CS(3-2) observations of the molecular gas associated with the Galactic starburst template NGC 3603, over an area of 5. � 8 ×16. 7, with the OB cluster at the center. Total velocity integrated maps and channel maps give insight into the spatial distribution and the kinematic structure of the dense gas in the giant molecular cloud from which the starburst cluster originated. We identify 13 molecular clumps with radii less than 0.8pc and derive upper limits for their virial masses as well as lower limits for their H2 column densities: �M vir� (0.4 ±0.2) ×10 23 cm −2 . One of the clumps, MM11, clearly stands out with a mass and column density 4 times higher than average. The CS(3-2) /CS(2-1) map shows higher intensity ratios to the south of the OB cluster than to the north (0.80 ± 0.08 versus 0.32 ± 0.11), which indicates a substantial difference in the physical conditions (either opacities or excitation temperatures) of the molecular gas. From the average of the line peak velocities, 14.2 ±1.6kms −1 , we deduce a kinematic distance of 7.7 ±0.2kpc for NGC3603. We estimate the star formation efficiency (>30%) of the central part of the NGC3603 H region. If we assume the age of the OB cluster to be less than 3Myr and the star formation rate to be larger than 1.3 ×10 −3 Myr −1 , the derived timescale for gas removal (τ ∼6Myr) can explain why the starburst cluster itself is nearly void of interstellar material. The remnant clump MM 1 appears to constitute the head of a prominent pillar which still becomes dispersed by ionizing radiation and stellar winds originating from the massive stars of the cluster. Because some of the molecular clumps are associated with near and mid infrared sources as well as OH, H2 Oa nd CH3OH maser sources we conclude that star formation is still going on within NGC 3603.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell