ar X iv : a st ro - p h / 99 02 24 7 v 1 1 7 Fe b 19 99 Dynamics of the Galaxy
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چکیده
Our Galaxy is a barred spiral. Recent work based on the COBE NIR data implies a small bulge–bar and a disk with a short scale-length. The corotation radius of the bar is in the range 3–4.5 kpc. The stellar density distribution beyond the end of the bar appears to be perturbed strongly by the Galaxy’s spiral arms. Gas flow calculations in corresponding potentials provide a qualitative explanation of many features observed in HI and CO lv-diagrams. These include the 3-kpc-arm and the apparent four–armed spiral structure between corotation and the solar radius. The mass of NIR–luminous matter is constrained by the terminal velocity curve, the Oort limit, and the bulge microlensing observations, and this implies that the Milky Way has a near-maximum disk and a dark halo with a large core radius of ∼ 15 kpc. However, we are still some way from a detailed quantitative model for the large–scale dynamics of the Galaxy. I summarize a number of uncertainties as well as how future work might resolve them.
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تاریخ انتشار 1999