THE DISTANCE OF THE SUN FROM THE GALACTIC -CENTER AND THE ROTATION CURVE FROM KINEMATIC HI AND HII DATA

By comparing the data on the rotation of HI Galactic sybsystems and HI I region/molecular cloud complexes, the distance to the center of the Galaxy was estimated to be R0 = 7.5 +/- 1.0 kpc. The uncertainty in th e derived estimate is mainly contributed by the errors in the distance s to HII regions. It is shown that for R0 to be correctly determined f rom these data, a detailed reproduction of the Galactic rotation curve is required. The effect of the HII regions in the Perseus spiral arm on the estimate of R0 was assessed. The Galactic rotation curve THETA( R) was constructed, and a smooth polynomial curve representing THETA(R ) in the interval 4 less-than-or-equal-to R less-than-or-equal-to 17 k pc was found.