Star formation scales and efficiency in Galactic spiral arms
Star formation scales and efficiency in Galactic spiral arms
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DOI：
10.1093/mnras/stv1323
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发表时间：
2015-06
影响因子：
4.8
通讯作者：
D. Eden;T. Moore;J. Urquhart;D. Elia;R. Plume;A. Rigby;M. Thompson
中科院分区：
文献类型：
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作者：
D. Eden;T. Moore;J. Urquhart;D. Elia;R. Plume;A. Rigby;M. Thompson
我们的位置相匹配的红外线选择的年轻恒星物体的样本，确定结合斯皮策银河遗产红外线中面调查非凡，宽视场红外线巡天探测器和赫歇尔空间天文台赫歇尔红外银河平面调查，在毫米连续确定的密集团块由Bolocam银河平面调查在两个银河视线集中在l = 30°和40°。我们计算的红外光度，LIR，质量的团块，Mclump，在各种银河系的环境中的比率，并发现它在一定程度上增强的螺旋臂相比，臂间区域时，平均超过千秒差距尺度。我们没有发现令人信服的证据表明，这些变化是由于机械影响的螺旋臂上的星星的形成效率，而不是，例如，不同的梯度在星星的形成率，由于补丁或间歇性星星的形成，或局部变化，不平均，由于小的源样本。LIR/Mclump的最大变化出现在个体丛数值中，其遵循对数正态分布，范围超过三个数量级。这种扩展是内在的，因为LIR/Mclump与Mclump没有依赖关系。在臂和臂间样本中，没有发现源的光度分布的差异，并且发现LIR和Mclump之间存在很强的线性相关性。
We positionally match a sample of infrared-selected young stellar objects, identified by combining the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire, Wide-field Infrared Survey Explorer and Herschel Space Observatory Herschel infrared Galactic Plane Survey, to the dense clumps identified in the millimetre continuum by the Bolocam Galactic Plane Survey in two Galactic lines of sight centred towards l = 30° and 40°. We calculate the ratio of infrared luminosity, LIR, to the mass of the clump, Mclump, in a variety of Galactic environments and find it to be somewhat enhanced in spiral arms compared to the interarm regions when averaged over kiloparsec scales. We find no compelling evidence that these changes are due to the mechanical influence of the spiral arm on the star formation efficiency rather than, e.g. different gradients in the star formation rate due to patchy or intermittent star formation, or local variations that are not averaged out due to small source samples. The largest variation in LIR/Mclump is found in individual clump values, which follow a lognormal distribution and have a range of over three orders of magnitude. This spread is intrinsic as no dependence of LIR/Mclump with Mclump was found. No difference was found in the luminosity distribution of sources in the arm and interarm samples and a strong linear correlation was found between LIR and Mclump.