FEEDBACK is a Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy project using the upGREAT heterodyne receiver to map the [CII] 158μm line in Galactic molecular clouds. It aims to study the interaction of massive stars with their environment in a sample of sources that span a range in stellar characteristics from single OB stars, to small groups of O stars, to rich young stellar clusters, to mini starbursts.
The aim of these observations is to quantify the mechanical energy injection and radiative heating efficiency in regions dominated by these different processes (stellar winds, thermal expansion, radiation pressure). This Legacy Program takes full advantage of the unique capabilities of the upGREAT/SOFIA combination: the high spatial (14″) and spectral (sub-km/s) resolution of the 14 element upGREAT heterodyne spectrometer coupled with the nimble telescope of SOFIA allows for efficient mapping of the [CII] line over large areas. With a total observing time of 96h, we will cover ~6000 arcmin^2 in 11 prominent Galactic sources. [CII] observations, together with the less explored [OI] 63μm line (observed in parallel), provide an outstanding data base for the community and will serve as a starting point for many studies and follow-up observations.