Stellar Winds and Embedded Star Formation in the Galactic Center Quintuplet and Arches Clusters: Multifrequency Radio Observations
Stellar Winds and Embedded Star Formation in the Galactic Center Quintuplet and Arches Clusters: Multifrequency Radio Observations
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银河系中心五联体和拱门星团中的恒星风和嵌入式恒星形成：多频率射电观测
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发表时间：
2005
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通讯作者：
Luis F. Rodriguez
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作者：
C. Lang;Kelsey E. Johnson;W. Goss;Luis F. Rodriguez
利用甚大阵对银河系中心五重星团和拱星团的致密射电源进行了多频、多组态的研究。在五重星系团中探测到了10个射电源。这些射电源中的大多数具有上升的光谱指数，并且与已知具有强大恒星风的年轻大质量恒星位置一致。我们的结论是，这些源中最紧凑的三个是由恒星风辐射产生的;因此，可以推导出质量损失率，平均值为3 × 10-5 M·yr-1。其余的来源可能是恒星风发射和周围电离气体的自由-自由发射的组合。在三种情况下，射电源没有对应的恒星，并且射电源被认为是来自致密或超致密的H II区域。如果是这样的话，这些来源将是在银河系中心星团中发现的嵌入式大质量恒星的第一个探测。与手枪星星有关的射电星云类似于围绕着明亮的蓝色变星星星η Car的星云，可能与手枪星星的恒星风有关。在拱门星团中还发现了10个致密射电源，并被解释为恒星风源，与以前的发现一致。几个来源显示出中等的变化（10%-30%），在其通量密度，可能与风排放的非热成分。两个星团中的一些射电源都有X射线对应物，这被解释为大质量双星系统的冲击，碰撞风。
A multifrequency, multiconfiguration study has been made of the compact radio sources in the Galactic center Quintuplet and Arches stellar clusters using the Very Large Array. Ten radio sources have been detected in the Quintuplet cluster. The majority of these radio sources have rising spectral indices and are positionally coincident with young massive stars that are known to have powerful stellar winds. We conclude that the three most compact of these sources are produced by stellar wind emission; thus, mass-loss rates can be derived and have an average value of 3 × 10-5 M⊙ yr-1. The remainder of the sources are likely to be a combination of stellar wind emission and free-free emission from surrounding ionized gas. In three cases, the radio sources have no stellar counterpart, and the radio emission is thought to arise from compact or ultracompact H II regions. If so, these sources would be the first detections of embedded massive stars to be discovered in the Galactic center clusters. The radio nebula associated with the Pistol star resembles the nebula surrounding the luminous blue variable star η Car and may be related to the stellar wind of the Pistol star. Ten compact radio sources are also detected in the Arches cluster and are interpreted to be stellar wind sources, consistent with previous findings. Several of the sources show moderate variability (10%–30%) in their flux density, possibly related to a nonthermal component in the wind emission. A number of radio sources in both clusters have X-ray counterparts, which have been interpreted to be the shocked, colliding winds of massive binary systems.