Study of the Galactic Rotation Based on Masers and Radio Stars with VLBI Measurements of Their Parallaxes (2009.04261v1)

Abstract: Based on published data, we have produced a sample of 256 radio sources whose trigonometric parallaxes and proper motions were measured by VLBI. This sample contains Galactic masers associated with massive protostars and stars in active star-forming regions. It also includes young low-mass stars from the Gould Belt region whose radio observations were performed in continuum. Based on this, most complete sample of sources to date, we have estimated the velocities $(U,V,W)\odot$ and the parameters of the angular velocity of Galactic rotation $\Omega_0, \Omega^{(1)}_0,... , \Omega^{(4)}_0$ and obtained a new estimate of the distance fromthe Sun to the Galactic center, $R_0=8.15^{+0.04}{-0.20}$ kpc. The parameters of the Galactic spiral density wave have been found from the series of radial, $V_R$, and residual tangential, $\Delta V_{circ}$, velocities of stars. The amplitudes of the radial and tangential velocity perturbations are $f_R=7.0\pm0.9$ km s$^{-1}$ and $f_\theta=3.8\pm1.1$ km s$^{-1}$, the perturbation wavelengths are $\lambda_R=2.3\pm0.2$ kpc and $\lambda_\theta=2.0\pm0.4$ kpc, and the Sun's phases in the spiral density wave are $(\chi_\odot)R=-163^\circ\pm9^\circ$ and $(\chi\odot)_\theta=-137^\circ\pm10^\circ$ for the adopted four-armed spiral pattern.