Clustering of Local Group distances: publication bias or correlated measurements? IV. The Galactic Center.
DE GRIJS R. and BONO G.
Abstract (from CDS):
Aiming at deriving a statistically well-justified Galactic Center distance, R0, and reducing any occurrence of publication bias, we compiled the most comprehensive and most complete database of Galactic Center distances available to date, containing 273 new or revised R0 estimates published since records began in 1918 October until 2016 June. We separate our R0 compilation into direct and indirect distance measurements. The latter include a large body of estimates that rely on centroid determinations for a range of tracer populations, as well as measurements based on kinematic observations of objects at the solar circle, combined with a mass and/or rotational model of the Milky Way. Careful assessment of the Galactic Center distances resulting from orbital modeling and statistical parallax measurements in the Galactic nucleus yields our final Galactic Center distance recommendation of R0=8.3±0.2 (statistical)±0.4 (systematic) kpc. The centroid-based distances are in good agreement with this recommendation. Neither the direct measurements nor the post-1990 centroid-based distance determinations suggest that publication bias may be important. The kinematics-based distance estimates are affected by significantly larger uncertainties, but they can be used to constrain the Galaxy's rotation velocity at the solar galactocentric distance, Θ0. Our results imply that the International-Astronomical-Union-recommended Galactic Center distance (R0IAU=8.5 kpc) needs a downward adjustment, while its Θ0 recommendation (Θ0=220 km s–1) requires a substantial upward revision.