FAR-INFRARED [C-II] LINE OBSERVATION OF THE GALACTIC PLANE BY IRTS

A detailed map of the distribution of the [C II] 158 mu m line intensi ty from the galactic plane around l = 50 degrees was obtained by the F ar-Infrared Line Mapper (FILM) on board the Infrared Telescope in Spac e (IRTS). The distribution of the [C II] emission is similar to that o f the far-infrared continuum emission. There are a number of discrete sources, most of which correspond to known objects, such as compact H II regions and molecular clouds, near to the galactic plane. Moreover, an extended component concentrated in the galactic plane was found, a nd its distribution does not clearly depend on the galactic longitude in the observed area. This extended component decreases rapidly as the galactic latitude increases. The FWHM of this component is about 2.de grees 6 in the galactic latitude. This is larger than that of the CO ( J = 1 --> 0) intensity, but is much smaller than that of the H I 21 cm intensity.