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arXiv 1803.09334astro-ph.GA
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大质量恒星形成III的无线电和红外协同巡天。北部超致密H II区的星表

The Coordinated Radio and Infrared Survey for High-Mass Star Formation III. A catalogue of northern ultra-compact H II regions

I. E. Kalcheva, M. G. Hoare, J. S. Urquhart, S. Kurtz, S. L. Lumsden, C. R. Purcell, A. A. Zijlstra

摘要:

本文给出了在5 GHz和1.5”分辨率下在$10^{\circ} < l < 65^{\circ}, ~|b| < 1^{\circ}$区的CORNISH巡天中发现的239个超致密HII区的目录。这是迄今为止最大的完整和精心挑选的UCHII样本,并提供了在多个波长下探索大质量恒星形成中这一关键状态的全球和个体属性的机会。候选人的性质进行了验证,根据观测特性和计算的光谱指数,并在这项工作中提出的分析。物理尺寸,光度和其他物理性质的计算,利用文献距离或计算的距离时,一个值是不可用的。测量了近红外和中红外扩展源通量,计算了对UCHII的散射。新的结果与现有的数据相结合,在较长的波长和光谱能量分布(SED)重建177 UCHIIs。给出了由SED拟合得到的辐射热光度值。通过与以前观测时期的射电通量密度进行比较,我们发现大约5%的源似乎是时变的。这是第一次对银河系平面进行高分辨率区域调查,显示银河系中UCHII的总数约为750 -比以前的大区域射电调查少3-4倍。它将成为未来大质量恒星形成模型测试的基础。

英文摘要:

A catalogue of 239 ultra-compact HII regions (UCHIIs) found in the CORNISH survey at 5 GHz and 1.5" resolution in the region $10^{\circ} < l < 65^{\circ}, ~|b| < 1^{\circ}$ is presented. This is the largest complete and well-selected sample of UCHIIs to date and provides the opportunity to explore the global and individual properties of this key state in massive star formation at multiple wavelengths. The nature of the candidates was validated, based on observational properties and calculated spectral indices, and the analysis is presented in this work. The physical sizes, luminosities and other physical properties were computed by utilising literature distances or calculating the distances whenever a value was not available. The near- and mid-infrared extended source fluxes were measured and the extinctions towards the UCHIIs were computed. The new results were combined with available data at longer wavelengths and the spectral energy distributions (SEDs) were reconstructed for 177 UCHIIs. The bolometric luminosities obtained from SED fitting are presented. By comparing the radio flux densities to previous observational epochs, we find about 5% of the sources appear to be time variable. This first high-resolution area survey of the Galactic plane shows that the total number of UCHIIs in the Galaxy is ~ 750 - a factor of 3-4 fewer than found in previous large area radio surveys. It will form the basis for future tests of models of massive star formation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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