2010MNRAS.402..934M

We reanalyse the measurements of parallax, proper motion and line-of-sight velocity for 18 masers in high-mass star-forming regions presented by Reid et al. We use a likelihood analysis to investigate the distance of the Sun from the Galactic Centre, R₀, the rotational speed of the local standard of rest, v₀, and the peculiar velocity of the Sun, v_☉, for various models of the rotation curve and models which allow for a typical peculiar motion of the high-mass star-forming regions.

We find that these data are best fit by models with non-standard values for v_☉ or a net peculiar motion of the high-mass star-forming regions. We argue that a correction to v_☉ is much more likely and these data support the conclusion of Binney that V_☉ should be revised upwards from 5.2 to 11km/s. We find that the values of R₀ and v₀ that we determine are heavily dependent on the model we use for rotation curve, with model-dependent estimates of R₀ranging from 6.7±0.5 to 8.9±0.9kpc, and those of v₀ ranging from 200 ±20 to 279±33km/s. We argue that these data cannot be thought of as implying any particular values of R₀ or v₀. However, we find that v₀/R₀ is better constrained, lying in the range 29.9 - 31.6km/s/kpc for all models but one.