A near-infrared (2.4 m) map of the galactic center region has been obtained by a balloon-borne telescope with a 1 resolution. The brightness distribution of the scanned area from l=350 to 27 within IbI 10 contains the galactic nuclear bulge, a very narrow ridge of the disk component, and some additional fine structures. We find that (i) the major and minor semi-axes of the nuclear bulge are 2.5 and 1.3 kpc, (ii) an apparent width of the disk component is 3?5 (FWHM), (iii) and a characteristic scale height of the interstellar dust layer is 150 pc. A tentative model of the Galaxy presented here defines an explicit form of the 2.4- m emissivity distribution as well as that of the interstellar dust distribution across the Galaxy. The model gives the total luminosity of the nuclear bulge to be 2 X 1010L , which is comparable to that of M31. Key words: Galactic structure; Infrared observation; Interstellar dust distribution; Nuclear bulge.
Publications of the Astronomical Society of Japan
- Pub Date: