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## Using VLBI observations of masers for studying the galaxy kinematics

Transactions of IAA RAS, issue 24, 294–298 (2012)

Keywords: radiointerferometry, Galactic rotation parameters, VLBI observations

### Abstract

The spatial velocities of all 28 currently known masers having trigonometric parallaxes, proper motion and line-of-site velocities are reanalyzed using the Bottlinger equations. These masers are associated with 25 active star-forming regions and are located in the range of galactocentric distances 3 < Ρ < 14 kpc. To determine the Galactic rotation parameters, we have used the first three Taylor expansion terms of angular rotation velocity _ at the galactocentric distance of the Sun, Ρ0 = 8 kpc. We have obtained the following solutions: ω = (-31.0 ± 1.2) km·s ^-1·kpc^-1; Oort constants, A = (17.8 ± 0.8) km·s⁻¹·kpc⁻¹, B = (-13.2 ± 1.5) km·s⁻¹·kpc⁻¹; the circular velocity of the solar neighbourhood rotation V0 = (248 ± 14) km·s⁻¹. A Fourier analysis of the galactocentric radial velocities of masers VR has allowed us to estimate the wavelength λ = (2.0 ± 0.2) kpc and peak velocity fR = (6.5 ± 2) km·s⁻¹ of periodic perturbations from the density wave. The phase of the Sun in the density wave is estimated as χ0 ≈ (-130 ± 10)°. Taking into account perturbations evoked by the spiral density wave, we have obtained the following non-perturbed components of the peculiar solar velocity with respect to the local standard of rest (LSR): (U0, V0, W0)LSR = [(5.5, 11, 8.5) ± (2, 2, 1)] km·s⁻¹.

### Citation

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V. V. Bobylev, A. T. Bajkova . Using VLBI observations of masers for studying the galaxy kinematics // Transactions of IAA RAS. — 2012. — Issue 24. — P. 294–298. @article{bobylev2012, abstract = {The spatial velocities of all 28 currently known masers having trigonometric parallaxes, proper motion and line-of-site velocities are reanalyzed using the Bottlinger equations. These masers are associated with 25 active star-forming regions and are located in the range of galactocentric distances 3 < Ρ < 14 kpc. To determine the Galactic rotation parameters, we have used the first three Taylor expansion terms of angular rotation velocity _ at the galactocentric distance of the Sun, Ρ0 = 8 kpc. We have obtained the following solutions: ω = (-31.0 ± 1.2) km·s ^-1·kpc^-1; Oort constants, A = (17.8 ± 0.8) km·s⁻¹·kpc⁻¹, B = (-13.2 ± 1.5) km·s⁻¹·kpc⁻¹; the circular velocity of the solar neighbourhood rotation V0 = (248 ± 14) km·s⁻¹. A Fourier analysis of the galactocentric radial velocities of masers VR has allowed us to estimate the wavelength λ = (2.0 ± 0.2) kpc and peak velocity fR = (6.5 ± 2) km·s⁻¹ of periodic perturbations from the density wave. The phase of the Sun in the density wave is estimated as χ0 ≈ (-130 ± 10)°. Taking into account perturbations evoked by the spiral density wave, we have obtained the following non-perturbed components of the peculiar solar velocity with respect to the local standard of rest (LSR): (U0, V0, W0)LSR = [(5.5, 11, 8.5) ± (2, 2, 1)] km·s⁻¹.}, author = {V.~V. Bobylev and A.~T. Bajkova}, issue = {24}, journal = {Transactions of IAA RAS}, keyword = {radiointerferometry, Galactic rotation parameters, VLBI observations}, pages = {294--298}, title = {Using VLBI observations of masers for studying the galaxy kinematics}, url = {http://iaaras.ru/en/library/paper/868/}, year = {2012} } TY - JOUR TI - Using VLBI observations of masers for studying the galaxy kinematics AU - Bobylev, V. V. AU - Bajkova, A. T. PY - 2012 T2 - Transactions of IAA RAS IS - 24 SP - 294 AB - The spatial velocities of all 28 currently known masers having trigonometric parallaxes, proper motion and line-of-site velocities are reanalyzed using the Bottlinger equations. These masers are associated with 25 active star-forming regions and are located in the range of galactocentric distances 3 < Ρ < 14 kpc. To determine the Galactic rotation parameters, we have used the first three Taylor expansion terms of angular rotation velocity _ at the galactocentric distance of the Sun, Ρ0 = 8 kpc. We have obtained the following solutions: ω = (-31.0 ± 1.2) km·s ^-1·kpc^-1; Oort constants, A = (17.8 ± 0.8) km·s⁻¹·kpc⁻¹, B = (-13.2 ± 1.5) km·s⁻¹·kpc⁻¹; the circular velocity of the solar neighbourhood rotation V0 = (248 ± 14) km·s⁻¹. A Fourier analysis of the galactocentric radial velocities of masers VR has allowed us to estimate the wavelength λ = (2.0 ± 0.2) kpc and peak velocity fR = (6.5 ± 2) km·s⁻¹ of periodic perturbations from the density wave. The phase of the Sun in the density wave is estimated as χ0 ≈ (-130 ± 10)°. Taking into account perturbations evoked by the spiral density wave, we have obtained the following non-perturbed components of the peculiar solar velocity with respect to the local standard of rest (LSR): (U0, V0, W0)LSR = [(5.5, 11, 8.5) ± (2, 2, 1)] km·s⁻¹. UR - http://iaaras.ru/en/library/paper/868/ ER -