Observations

Candidate YSO locations were identified using the SED fitter tool developed by Robitaille et al. (2006, 2007). Briefly, this method uses the 2MASS and GLIMPSE point source catalogues to identify sources that are not well-fit by main-sequence SEDs and are well-fit by YSO SEDs. \citet{Watson_2010} fit all point sources within 1’ of the bubble edges using this method. From this set of point sources, four sources were selected near each bubble based on association with either diffuse, bright 8 \(\mu\)m emission or IR dark clouds. Forty point sources in total were selected. The names, Galactic longitude and Galactic latitude are reported in Table 2. Each point source was observed for CS using the Green Bank Telescope (GBT) for two 5 minute integrations. The spectrometer was set-up in frequency switching mode to maximize on-source observing time. The setup parameters and calibration sources are listed in Table 1.

\label{configuration}

Observing Parameters

Data were calibrated and analyzed using GBTIDL. Typical system temperatures were between 105 K and 120 K. Typical rms noise in the resulting calibrated spectra was 0.20 K. Non-detections and detections are listed in Tables 2 and 3, respectively. We estimate uncertainty due to flux calibration of 20%.

In addition to single pointings, we mapped three regions (N56, N65 2 and N77 1) that displayed strong CS emission. The map sizes were 1’x1’ (N56 and N77-1) and 2’x2’ (N65-2), both using a Nyquist-sampling step-size of 6.12".

We also used observations of all of the sources in this study from Hi-Gal \cite{Molinari_2010}, a Herschel Space Telescope imaging survey of the Galactic plane conducted at wavelengths between 60 \(\mu\)m and 600 \(\mu\)m. Data were downloaded from the Spitzer Science Center website. Fully calibrated Level 2 data products were used.

CS Non-Detections