Determination of Galactic Rotation Parameters and the Solar Galactocentric Distance Ro from 73 Masers

TL;DR

This study precisely determines the Galactic rotation parameters and the solar Galactocentric distance using VLBI measurements of 73 masers, providing a highly accurate estimate of R_0 that aligns with recent findings.

Contribution

First to estimate the solar Galactocentric distance R_0 from maser data with high accuracy, improving the precision of Galactic rotation parameters.

Findings

Galactic rotation parameters are Omega_0=28.86 km/s/kpc, Omega'_0=-3.96 km/s/kpc^2, Omega''_0=0.790 km/s/kpc^3.

Solar Galactocentric distance R_0=8.3 kpc with 0.2 kpc uncertainty.

Linear rotation velocity at R_0 is 241 km/s.

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 Omega_0 = 28.86 +/- 0.45 km/s/kpc, Omega'_0 = -3.96 +/- 0.09 km/s/kpc^2, Omega"_0 =0.790 +/- 0.027 km/s/kpc^3, and R_0=8.3 +/- 0.2 kpc.In this case, the linear rotation velocity at the solar distance Ro is V_0=241 +/- 7 km/s. Note that we have obtained the Ro 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.