... protostars[*]
Based on observations with the IRAM 30 m telescope at Pico Veleta (Spain). IRAM is funded by the INSU/CNRS (France), the MPG (Germany) and the IGN (Spain). 
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...[*]
Figures 7-12 and Tables 6-9 are only available in electronic form at http://www.edpsciences.org 
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... densities[*]
For example, for CH2DOH, the Einstein coefficients for the observed transitions lie in the 10-6 to 10-5 s-1 range. The collisional de-excitation rates are expected to be on the order of 10-11 cm3 s-1, leading to critical densities of 105 to 106 cm3. 
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Copyright ESO 2006