Vol 18, No 10

Gas compression and likely triggered star formation in the infrared bubble N107

There are currently no refbacks. Hao Li, Jin-Zeng Li, Jing-Hua Yuan, Ya-Fang Huang, Zhi-Yuan Ren


The expansion of HII regions can regulate the evolution of their natal clouds and the star formation therein. Infrared dust bubbles, which are frequently associated with HII regions, are ideal laboratories to test whether impulse(s) driven by the expanding bubbles enhances or suppresses star-formation. In this work, we present a comprehensive study of a 20-pc scale infrared bubble N107 to reveal the compression of the neutral gas and associated star-forming activities. We obtain column density (NH2) and dust temperature (Tdust) maps via fitting modified blackbodies to multi-band far-infrared Herschel data. The shell structure can be recognized on the column density map. The molecular gas along the rim of N107 fragments into 94 dense clumps at an angular resolution of 18′′. Besides, based on the GLIMPSE point source catalog, we have identified 228 young stellar objects (YSOs) which are categorized into 55 Class I objects, 127 Class II objects and 46 transition disks (TDs). The 94 clumps and 55 Class I type YSOs are mainly distributed along the shell, which may suggest triggered star formation exists in N107. In addition, analysis of NH2 probability density functions (PDFs) helps us reveal the condition of natal clouds. The two lognormal profiles of PDFs suggest that the surrounding molecular gas has been compressed due to expansion of the bubble. This compression may trigger the star formation process. Moreover, we find the shape of the PDFs changed after removing the background. Taken together, this big bubble seems to compress the surrounding gas and strongly regulate star formation therein.


ISM: HII regions — ISM: clouds — stars: formation — ISM: structure — methods: observational

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