Recent advances in the determination of some Galactic constants in the Milky Way

TL;DR

This paper reviews recent statistical measurements of key Galactic constants like the Sun-Galactic Center distance and orbital velocities, confirming values around 8 kpc and 230 km/s, and discusses their implications for spiral structure models.

Contribution

It provides a comprehensive statistical evaluation of recent measurements of Galactic constants, refining their values and comparing them with density wave model predictions.

Findings

Rsun = 8.0 +- 0.2 kpc

Vlsr = 230 +- 3 km/s

Angular rotation near 29 +- 1 km/s/kpc for local objects

Abstract

Here we statistically evaluate recent advances in determining the Sun-Galactic Center distance (Rsun) as well as recent measures of the orbital velocity around the Galactic Center (Vlsr), and the angular rotation parameters of various objects. Recent statistical results point to Rsun = 8.0 +- 0.2 kpc, Vlsr= 230 +- 3 km/s, and angular rotation at the Sun ({\omega}) near 29 +- 1 km/s/kpc for the gas and stars at the Local Standard of Rest, and near 23 +- 2 km/s/kpc for the spiral pattern itself. This angular difference is similar to what had been predicted by density wave models, along with the observation that the galactic longitude of each spiral arm tracer (dust, cold CO) for each spiral arm becomes reversed across the Galactic Meridian (Vallee 2016b).