The C+ Universe

The interaction of massive stars with their environments regulates the evolution of galaxies. Mechanical and radiative energy input by massive stars stir up and heat the gas and control cloud and intercloud phases of the interstellar medium. Stellar feedback also governs the star formation efficiency of molecular clouds. On the one hand, stellar feedback can lead to ashredding of the nascent molecular cloud within a few cloud free-fall times thereby halting star formation. On the other hand, massive stars can also provide positive feedback to star formation as gravity can more easily overwhelm cloud-supporting forces in swept-up compressed shells. Moreover, stellar feedback is an important source of turbulence in the interstellar medium. The combination of sensitive THz heterodyne receiver arrays with a nimble telescope on SOFIA enables large scale, [CII] 158µm surveys of regions of massive star formation. This line is the main cooling line of neutral gas in the interstellar medium and therefore a key diagnostic of interstellar gas energy balance. In addition, the high spectral resolution inherent to heterodyne techniques allows a detailed study of the kinematics of photodissociation regions, which separate ionized from molecular gas. I will present results of the [CII] 158µmsquare degree Orion Survey and the SOFIA/upGREAT FEEDBACK Legacy Program, their analysis and implications for the interaction of massive stars with their environment and their role in the evolution of galaxies.