For information on how to participate in the Tele-Talks, please check the SOFIA Tele-Talk page.
Far-infrared lines are essential tracers of the gas cooling and heating processes induced by shocks and UV radiation during the early phases of star formation. Observations of high-J CO (J_up ≥14), OH, [OI], [CII] allow us to constrain the gas temperatures, densities, and UV fields in embedded objects. However, the cooling via these far-infrared lines might depend on the conditions of the environment, e.g., metallicity. In this talk, I will deliver our results from SOFIA FIFI-LS spectra toward the embedded cluster Gy 3-7 in the CMa-l224 star-forming region in the outer Galaxy which has a metallicity of ~0.55-0.73 Z_sun. I will present our measurements of CO rotational temperatures, the strength of UV radiation, and gas number density across the cluster. I will show that the CO rotational temperatures in Gy 3-7 are consistent with what is found in other intermediate-mass young stellar objects in the inner Galaxy. Assuming the [OI] and CO lines arise from the UV-irradiated C-shocks in the region, the UV radiation fields (G0~ 0.1-10) and gas densities (n_H ~ 10^4 - 10^5 cm^{-3}) are estimated in the cluster. The FIFI-LS spectrometer onboard SOFIA constitutes an important tool to study the physical conditions of dust and gas in deeply embedded clusters like Gy 3-7 and also to test the impact of metallicity on the gas cooling.