By Cristian Guevara and Joan Schmelz
Paper: [C II] 158 µm self-absorption and optical depth effects
Guevara, C., et al., 2020/04, A&A, 636A, A16.
Photodissociation Regions (PDRs) are zones of the interstellar medium in which Far-UV photons dominate the thermal balance, chemistry, structure, as well as the distribution of the gas and dust. The incident FUV field photodissociates molecules, photoionizes atoms and molecules, and heats the gas and dust.