Infrared observations of the nuclear region

Infrared observations have provided considerable information about the structure and energetics of the galactic center. The stellar bulge dominates the mass and luminosity of the nuclear region. The luminosity of the bulge is strongly peaked toward the center, even within the central parsec. Dust in the nuclear disk absorbs the power output of the central portion of the bulge and reemits it in the far infrared. Near the center, molecular clouds move in a plane apparently tilted toward the Sun. Within the central few parsecs, or core , the inclination may be as large as 450. The total power output of the core is about twice that of the bulge population alone. The source of excess luminosity is uncertain, but evidence points to ongoing star formation associated with the Sgr A molecular complex. (Auth.)