Far-Infrared Spectral Observations of the Galaxy by the Far-Infrared Absolute Spectrophotometer

The Galactic continuum spectrum from 5–96 cm−1 is derived from COBE1 /FIRAS observations. The spectra are dominated by warm dust emission, which may be fit with a single temperature along each line of sight in the range 16–21 K. A widespread, very cold component (4–7 K) with optical depth that is spatially correlated with the warm component is also detected. The nature of the cold component and its implications for the amount of very cold material in the Milky Way are discussed.