deletions | additions       diff --git a/section_Introduction_Massive_stars_strongly__.tex b/section_Introduction_Massive_stars_strongly__.tex  index 5f0f089..ada4e6c 100644  --- a/section_Introduction_Massive_stars_strongly__.tex  +++ b/section_Introduction_Massive_stars_strongly__.tex 
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The selection of bubbles with an overabundance of YSOs along the bubble-ISM boundary are a potentially excellent set of sources to study the mechanisms of triggered star-formation. The method of identifying YSOs through photometry, however, is limited. Robitaille \& Whitney (20XX) showed that YSO age is degenerate with the observer's inclination angle. Briefly, a late-stage YSO seen edge on, so the accretion disk is observed as thick and blocking the inner regions, will appear similar, even in the IR, so an early stage YSO. Thus, we require other diagnostics of the YSOs along the bubble edge to determine the youngest, and most likely to have been triggered, YSOs.   The current project aimed to identify the youngest YSOs by observing the CS (1-0) transition near 49 GHz with the Green Bank Telescope (GBT). CS is a probe of young star-formation. It has been detected in outflows from protostars, infall and in hot cores (citations?). The chemistry is, naturally, complex, and it appears that CS can play several roles. Our aim here is to use CS as a broad identifier of young star-formation and use any non-gaussian line-shapes to infer molecular gas behavior.  After describing the observations (sec 2) and numerical results (sec 3), we analyze the Herschel-HiGAL emission toward all our sources to determine, along with the CS detections, the CS abundance (sec 4.1). We also analyze three sources for evidence of infall (sec 4.2).