Cornelia Pabst
Leiden University
To Bubble or Not to Bubble: Stellar feedback in Orion and 30 Doradus
The interaction of massive stars with their environments regulates the evolution of galaxies. Specifically, through their radiation and their winds, massive stars disrupt their environment and disturb their nascent molecular cloud. The combination of the sensitive THz heterodyne receiver arrays upGREAT with a nimble telescope on SOFIA enabled large-scale [CII] 158 μm 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 the interstellar gas energy balance. It also provides a unique window on stellar feedback. 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 compare and contrast the results of the [CII] 158 μm survey of the Orion Nebula with those of the 30 Doradus region in the LMC. The Orion Nebula is the nearest region of massive star formation and these observations allow a detailed and in-depth analysis of the effects of a single massive star on its environment. In contrast, 30 Doradus in the LMC is the nearest birth site of a super star cluster, where ~1000 OB stars are disrupting the molecular cloud in which they were formed. A significant amount of the input mechanic and radiative energy is dissipated on scales smaller than 14” (3.4 pc at a distance of 50 kpc), the resolution of SOFIA at 158 μm, as has previously been suggested by observations of the ionized gas. This renders the lines broader than expected. The observed correlation between the [CII] line intensity and broadband infrared intensities is less than in the Orion Nebula complex, and we relate this to the heating rate of neutral gas by PAHs.
