Exploring the Relationships Between [CII] and Dust Emission in Nearby Galaxies

The 158 micron line produced by singly-ionized carbon ([CII]) has become a popular tool for assessing interstellar medium (ISM) conditions in galaxies near and far. One of the major cooling channels in photodissociation regions (PDRs), the [CII] line has been suggested as a tracer of star formation rate, shock-heated gas, CO dark molecular gas, and atomic gas. In order to determine the applicability of this emission line to this variety of diagnostics, it is essential to study the spatially-resolved [CII] emission in nearby galaxies. Using archival maps of [CII] emission in nearby galaxies produced by FIFI-LS onboard SOFIA and PACS onboard Herschel, we will perform a systematic analysis of the [CII] emission as a function local environment. Through analysis of multiwavelength photometry, we will compare the [CII] emission to the dust emission measured by the far-infrared (FIR) luminosity and the polycyclic aromatic hydrogen (PAH) emission features. By compiling the data from multiple surveys, we will be able to better constrain the possible causes of the notorious [CII] deficit, measured as the decreasing trend in [CII]/FIR with increasing FIR luminosity. We complete this analysis with our new pipeline for reducing unchopped PACS spectroscopy, which reduces the uncertainty in the archival data. In this presentation we will provide the current status of this project and a summary of the planned data products.