STATISTICAL PROPERTIES OF 12.2 GHz METHANOL MASERS ASSOCIATED WITH A COMPLETE SAMPLE OF 6.7 GHz METHANOL MASERS
STATISTICAL PROPERTIES OF 12.2 GHz METHANOL MASERS ASSOCIATED WITH A COMPLETE SAMPLE OF 6.7 GHz METHANOL MASERS
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DOI：
10.1088/0004-637x/733/2/80
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
S. Breen;S. Ellingsen;J. Caswell;J. Green;G. Fuller;M. Voronkov;L. Quinn;A. Avison
中科院分区：
文献类型：
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作者：
S. Breen;S. Ellingsen;J. Caswell;J. Green;G. Fuller;M. Voronkov;L. Quinn;A. Avison
我们对12.2 GHz甲醇脉泽的确定性检测统计，对6.7 GHz甲醇脉泽的完整样本检测甲醇多波束调查南10月-20 °。总共，我们检测到250 12.2 GHz甲醇脉泽对580 6.7 GHz甲醇脉泽。这相当于43.1%的检出率，低于之前具有可比灵敏度的重要检索的检出率。目标6.7 GHz源的速度范围和通量密度在几乎所有情况下都超过了它们的12.2 GHz同伴。80%的12.2GHz甲醇脉泽峰与6.7GHz甲醇脉泽峰速度一致。我们的数据支持一个进化的情况下，12.2 GHz的源与6.7 GHz的源，没有这种过渡的一个稍晚的进化阶段。此外，我们发现，6.7 GHz和12.2 GHz的甲醇源的光度增加，因为它们的演变。除此之外，证据的速度范围与进化的增加。这意味着，不仅是光度，而且气体的体积有助于不同的脉泽过渡，随着源的发展而增加。与GLIMPSE中红外源的比较表明，6.7 GHz甲醇脉泽和GLIMPSE点源的位置之间的重合率与以前的研究中所取得的结果相似。总的来说，GLIMPSE源（有和没有12.2 GHz对应物）的特性是相似的。与扩展绿色天体重合的6.7 GHz甲醇脉泽有较高的12.2 GHz探测率。
We present definitive detection statistics for 12.2 GHz methanol masers toward a complete sample of 6.7 GHz methanol masers detected in the Methanol Multibeam survey south of declination −20°. In total, we detect 250 12.2 GHz methanol masers toward 580 6.7 GHz methanol masers. This equates to a detection rate of 43.1%, which is lower than that of previous significant searches of comparable sensitivity. Both the velocity ranges and the flux densities of the target 6.7 GHz sources surpass that of their 12.2 GHz companion in almost all cases. Eighty percent of the detected 12.2 GHz methanol maser peaks are coincident in velocity with the 6.7 GHz maser peak. Our data support an evolutionary scenario whereby the 12.2 GHz sources are associated with a somewhat later evolutionary stage than the 6.7 GHz sources devoid of this transition. Furthermore, we find that the 6.7 GHz and 12.2 GHz methanol sources increase in luminosity as they evolve. In addition to this, evidence for an increase in velocity range with evolution is presented. This implies that it is not only the luminosity but also the volume of gas conducive to the different maser transitions that increases as the sources evolve. Comparison with GLIMPSE mid-infrared sources has revealed a coincidence rate between the locations of the 6.7 GHz methanol masers and GLIMPSE point sources similar to that achieved in previous studies. Overall, the properties of the GLIMPSE sources with and without 12.2 GHz counterparts are similar. There is a higher 12.2 GHz detection rate toward those 6.7 GHz methanol masers that are coincident with extended green objects.