A statistical analysis of methanol maser groups

被引：0
作者：
I. E. Val’tts
S. Yu. Lyubchenko
机构：
[1] Russian Academy of Sciences,Astro Space Center, Lebedev Physical Institute
来源：
Astronomy Reports | 2004年 / 48卷
关键词：
Methanol; Spectral Feature; Flux Density; Linear Dependence; Maser Group;
D O I：
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中图分类号：
学科分类号：
摘要：
An analysis of the flux densities of the 51-60A+ (6.7 GHz) and 20-3−1E (12.2 GHz) class II methanol maser lines in a large and homogeneous sample of maser sources has been carried out. For convenience, the maser lines were divided into three groups: group I contains spectral features for the lines most prominent in the 51-60A+ (6.7 GHz) transition, group II contains spectral features for the lines strongest in the 20-3−1E (12.2 GHz) transition, group III contains spectral features for which the velocities of the emission maxima of the two lines coincide. The same dependence was found for group II and group III: log S6.7=(0.79±0.05)×log S12.2+(0.79±0.05). The spectral features in group I do not obey this relation, and deviations from a linear dependence are considerably greater. It is suggested that methanol class II masers be divided into a subclass IIa, which has special conditions favoring 6.7 GHz masers, and a subclass IIb, which is comprised of the 12.2 GHz masers and those 6.7 GHz masers that necessarily accompany them under the same conditions.
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页码：834 / 839
页数：5
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