| 초록 |
A model for the distribution of stars in the disk and the spheroid of our Galaxy is reexamined from an edge-on view of the Galaxy obtained by selecting infrared sources from the IRAS Point Source Catalog. The sources are counted as a function of galactic latitude. longitude and $12{ mu}m$ apparent magnitude. The source counts are reasonably separated into the disk component and the spheroid component contributions and each of the contributions is further interpreted as a convolution of a spatial density distribution and a luminosity function based on the least-square fit method. The spatial density of the disk component has an exponential radial scale length of $h_R{ sim}2.6 ;kpc$ and the vertical distribution follows a canonical $sech^2$ law with a scale height $h_z{ sim}240 ;pc$ . The distribution of the spheroid component can be represented by an oblate spheriod with an axis ratio $k{ sim}0.61$ and a de Vaucouleurs' $r^{1/4}$ law with an effective radius of $R_e{ sim}120 ;pc$ . The steep density gradient of the spheroid component is consistent with that of late M giants in the central bulge. The luminosity functions of the disk and the spheroid component stars resemble respectively those of the K luminosity function of disk M giants (Garwood and Jones 1986) and the bolometric luminosity function of M giants in bulge fields (Frogel et al, 1990). |
