SQUARE_BRACKET_OPENCIISQUARE_BRACKET_CLOSE Observations of the Unexplored Atomic Gas-Rich ISM in Nearby Galaxies

We propose deep CII mapping of atomicgas dominated regions in several nearby galaxies. These regions represent interstellar medium conditions that have not yet been explored with Herschel or any other facility and will remain unexplored in the foreseeable future if they are not observed with Herschel in OT2. We will use the proposed CII observations to measure the ISM heating rate and constrain the heat source in regions where the photoelectric effect driven by ultraviolet photons from young stars does not dominate. These observations are crucial for characterizing the low surface brightness CII emission, which is potentially an important contributor to the total CII emission from galaxies. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]