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arXiv · 1411.2508

Analysis of Galactic Rotation from Masers based on a Nonlinear Oort Model

V. V. Bobylev·A. T. Bajkova
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Abstract

Based on data on Galactic masers with measured trigonometric parallaxes, we have tested a nonlinear model of Galactic rotation using generalized Oort formulas. This model is shown to yield pretty good results up to heliocentric distances of 3--4 kpc. The main feature of the method is the possibility of estimating the solar Galactocentric distance Ro. This distance has been found by analyzing approximately 60 masers to be Ro=8.3+/-0.4 kpc. Our study of the three-dimensional kinematics of more than 100 masers based on the Ogorodnikov--Milne model has shown that significant nonlinearities are present only in the xy plane (rotation around the Galactic z axis) due to the peculiarities of the Galactic rotation curve. No significant linear dependences have been found in the xz and yz planes. We show the presence of a wave in the velocities w as a function of coordinate x or distance R with a wavelength of 3 kpc and an amplitude of 10 km/s. The wave is particularly prominent in the Local and Perseus arms.

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V. V. Bobylev, A. T. Bajkova. 2014-11-10. Analysis of Galactic Rotation from Masers based on a Nonlinear Oort Model. https://doi.org/10.1134/s1063773714120019

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