Determination of galactic rotation parameters and the solar galactocentric distance R 0 from 73 masers

Abstract

We have determined the Galactic rotation parameters and the solar Galactocentric distance R 0 by simultaneously solving Bottlinger’s kinematic equations using data on masers with known line-of-sight velocities and highly accurate trigonometric parallaxes and proper motions measured by VLBI. Our sample includes 73 masers spanning the range of Galactocentric distances from 3 to 14 kpc. The solutions found are Ω0 = 28.86 ± 0.45 km s−1 kpc−1, Ω′0 = −3.96 ± 0.09 km s−1 kpc−2, Ω″0 = 0.790 ± 0.027 km s−1 kpc−3, and R 0 = 8.3 ± 0.2 kpc. In this case, the linear rotation velocity at the solar distance R 0 is V = 241 ± 7 km s−1. Note that we have obtained the R 0 estimate, which is of greatest interest, from masers for the first time; it is in good agreement with the most recent estimates and even surpasses them in accuracy.