The Unidentified Infrared Bands in the Diffuse Interstellar Medium across the Galaxy Based on the Infrared Telescope in Space Mid-Infrared Spectrometer Observation

We present the results of observations of the unidentified infrared (UIR) bands in the diffuse Galactic emission across the Galaxy by the Mid-Infrared Spectrometer (MIRS) on board the Infrared Telescope in Space (IRTS). While previous studies on the UIR bands in the Milky Way were limited to the inner Galactic plane, we extend the observing area to the outer Galactic plane. In this paper we analyze the data of four areas of 8 super([j0]) x 8 super([j0]) around the Galactic plane (|b| < 4 super([j0]); -12 super([j0]) < l