12. Infrared Observations of the Galactic Center

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Infrared radiation from the nucleus of the galaxy has been detected at effective wavelengths of 1.65, 2.2, 3.4 and 4.8 […] with angular resolutions from 0.04 to 1.8 arc min. Observations have been made over an area of 1 square degree surrounding the dynamical center of the Galaxy. The reduced data consist of contour maps of the 2.2 […] brightness distribution of the galactic center region for resolutions of 1.8, 0.8, and 0.25 arc min, and of tabulations of the 1.65, 2.2, 3.4, and 4.8 […] flux densities and surface brightnesses at various areas in the galactic center region. From the brightness distribution maps it is found that the structure consists of: (1) a dominant source 5 arc min in diameter, (2) a point-like source centered on the dominant source, (3) an extended background approximately 1 degree in diameter, (4) additional discrete extended sources which are fainter than the dominant source. A comparison of the infrared and radio observations shows that the dominant infrared source and the radio source Sagittarius A have the same coordinates and similar sizes. An analysis of the observed infrared radiation predicts about 25 magnitudes of visual absorption between the Sun and the galactic center if the source of infrared radiation is stellar. A comparison is also made between the infrared radiation from the galactic center and that from the nucleus of M 31 which shows agreement in both the apparent structure and infrared luminosity of the two nuclei.