Orion's Dragon and Other Stories
Stellar feedback is a crucial ingredient in the evolution of galaxies.
- Pabst, C.H.M.
- 18 March 2021
- Thesis in Leiden University Scholarly Publications
Stellar feedback is a crucial ingredient in the evolution of galaxies. Massive stars disrupt their natal molecular clouds and perturb the ambient interstellar medium, not only when they explode as supernovae but also during their lifetimes by stellar winds and radiation. The irradiated, heated, and stirred gas cools through the emission of fine-structure lines. The far-infrared fine-structure line of ionized carbon is the dominant coolant of warm neutral gas and has been suggested as a powerful tracer of the star-formation rate (a derivative of stellar feedback) in distant galaxies. This thesis aims to explore the origins of the [CII] emission and to quantify stellar feedback observationally in local samples. I have used high-resolution (both spectral and angular) observations of the [CII] line obtained with the upGREAT instrument onboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) of the Horsehead Nebula and the Orion Nebula at the surface of the Orion molecular cloud. This nearby template star-forming region allows to study physical properties of the irradiated gas and to precisely determine the amount of kinetic energy deposited in the expanding bubbles surrounding the massive stars.