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arXiv 0803.2404astro-ph
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II Zw 40的积分场近红外光谱

Integral field near-infrared spectroscopy of II Zw 40

L. Vanzi, G. Cresci, E. Telles, J. Melnick

备注：
Accepted for publication on A&A
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摘要：

我们提出了积分场光谱在近红外附近的星暴星系IIZw40。我们的新观测提供了这个星系的星际介质和恒星形成的前所未有的详细视图。星系发出的辐射主要由一个巨大的HII区域控制，该区域的面积超过400 pc。这个区域有几个星团，但其中一个似乎是电离光子的主要来源。我们推导了这个天体的性质，并将其与大麦云（LMC）中的剑鱼座30星系团的性质进行了比较。我们主要通过X射线谱线、分子氢谱和[Fe Ⅱ]研究了星际介质（ISM）中不同组分的空间分布和速度场。我们发现[Fe Ⅱ]和H_2主要是光子激发的，而[Fe Ⅱ]的发射区与在H和He原子谱线上观察到的巨H_2区几乎一致，而H_2在空间和速度上的分布则完全不同。主星团中恒星星族的年龄是这样的，以至于还没有超新星（SN）出现，所以气体运动学必须由年轻恒星主导。我们没有看到，在恒星爆发区域，任何几何或动力学结构，可以与大尺度的星系形态。

英文摘要：

We present integral field spectroscopy in the near-infrared of the nearby starburst galaxy IIZw40. Our new observations provide an unprecedented detailed view of the interstellar medium and star formation of this galaxy. The radiation emitted by the galaxy is dominated by a giant HII region, which extends over an area of more than 400 pc in size. A few clusters are present in this area, however one in particular appears to be the main source of ionizing photons. We derive the properties of this object and compare them with those of the 30 Doradus cluster in the Large magellanic cloud (LMC). We study the spatial distribution and velocity field of different components of the inetrstellar medium (ISM), mostly through the Bracket series lines, the molecular hydrogen spectrum, and [FeII]. We find that [FeII] and H2 are mostly photon excited, but while the region emitting [FeII] is almost coincident with the giant HII region observed in the lines of atomic H and He, the H2 has a quite different distribution in space and velocity. The age of the stellar population in the main cluster is such that no supernova (SN) should be present yet so that the gas kinematics must be dominated by the young stars. We do not see, in the starbursting region, any geometrical or dynamical structure that can be related to the large scale morphology of the galaxy.

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