Unformatted text preview: r = +30 km/s. Determine the galactic radius R of the gas at this radial velocity and its distance from us, d. Use R o = 8.5 kpc and V o = 220 km/s. Refer to Figure 16.9 for the rotation curve of the Galaxy. 5. Determine the proper motion relative to the LSR for a star in circular orbit about the Galactic center at a distance d = 5 kpc from the Sun (LSR) and at a galactic longitude of 45 degrees. Assume a flat rotation curve for the Galaxy as in Figure 16.9. 6. Given the luminosity profile in eq. 17.1 used to describe elliptical galaxies, what would the luminosity be at a) r = r o , b) r = 2r o ? Use L(0) = 2 x 10 5 L sun /pc 2 . 7. Given the luminosity profile in eq. 17.2 used to describe the disks of spiral galaxies, what would the luminosity be at a) r = D, b) r = 2D? Express your answer in terms of L o ....
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- Spring '08
- galactic center, rotation curve, galactic longitude