SIMBAD references

The brightest observed emission line in many star-forming galaxies is the [CII] 158 µm line, making it detectable up to z ∼ 7. In order to better understand and quantify the [CII] emission as a tracer of star formation, the theoretical ratio between the [NII] 205 µm emission and the [CII] 158 µm emission has been employed to empirically determine the fraction of [CII] emission that originates from the ionized and neutral phases of the interstellar medium (ISM). Sub-kiloparsec measurements of the [CII] 158 µm and [NII] 205 µm lines in nearby galaxies have recently become available as part of the Key Insights in Nearby Galaxies: a Far Infrared Survey with Herschel (KINGFISH) and Beyond the Peak programs. With the information from these two far-infrared lines along with the multi-wavelength suite of KINGFISH data, a calibration of the [CII] emission line as a star formation rate (SFR) indicator and a better understanding of the [CII] deficit are pursued. [CII] emission is also compared to polycyclic aromatic hydrocarbon (PAH) emission in these regions to compare photoelectric heating from PAH molecules to cooling by [CII] in the neutral and ionized phases of the ISM. We find that the [CII] emission originating in the neutral phase of the ISM does not exhibit a deficit with respect to the infrared luminosity and is therefore preferred over the [CII] emission originating in the ionized phase of the ISM as an SFR indicator for the normal star-forming galaxies included in this sample.