Influence of the Galactic bar on the kinematics of the disc stars with Gaia EDR3 data. (arXiv:2106.09531v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Melnik_A/0/1/0/all/0/1">A. M. Melnik</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dambis_A/0/1/0/all/0/1">A. K. Dambis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Podzolkova_E/0/1/0/all/0/1">E. N. Podzolkova</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Berdnikov_L/0/1/0/all/0/1">L. N. Berdnikov</a>
A model of the Galaxy with the outer ring R1R2 can explain the observed
distribution of the radial, VR, and azimuthal, VT, velocity components along
the Galactocentric distance, R, derived from the Gaia EDR3 data. We selected
stars from the Gaia EDR3 catalogue with reliable parallaxes, proper motions and
line-of-sight velocities lying near the Galactic plane, |z|<200 pc, and in the
sector of the Galactocentic angles |theta|<15 degrees and calculated the median
velocities VR and VT in small bins along the distance R. The distribution of
observed velocities appears to have some specific features: the radial velocity
VR demonstrates a smooth fall from +5 km s-1 at the distance of R=R0-1.5 kpc to
-3 km s-1 at R=R0+1.0 kpc while the azimuthal velocity VT shows a sharp drop by
7 km s-1 in the distance interval R0<R<R0+1.0 kpc, where R0 is the solar
Galactocentric distance. We build a model of the Galaxy including bulge, bar,
disc and halo components, which reproduces the observed specific features of
the velocity distribution in the Galactocentric distance interval |R-R0|< 1.5
kpc. The best agreement corresponds to the time 1.8+/-0.5 Gyr after the start
of the simulation. A model of the Galaxy with the bar rotating at the angular
velocity of Omega_b=55+/-3 km s-1 kpc-1, which sets the OLR of the bar at the
distance of R0-0.5+/-0.4 kpc, provides the best agreement between the model and
observed velocities. The position angle of the bar, theta_b, corresponding to
the best agreement between the model and observed velocities is theta_b=45+/-15
degrees.
A model of the Galaxy with the outer ring R1R2 can explain the observed
distribution of the radial, VR, and azimuthal, VT, velocity components along
the Galactocentric distance, R, derived from the Gaia EDR3 data. We selected
stars from the Gaia EDR3 catalogue with reliable parallaxes, proper motions and
line-of-sight velocities lying near the Galactic plane, |z|<200 pc, and in the
sector of the Galactocentic angles |theta|<15 degrees and calculated the median
velocities VR and VT in small bins along the distance R. The distribution of
observed velocities appears to have some specific features: the radial velocity
VR demonstrates a smooth fall from +5 km s-1 at the distance of R=R0-1.5 kpc to
-3 km s-1 at R=R0+1.0 kpc while the azimuthal velocity VT shows a sharp drop by
7 km s-1 in the distance interval R0<R<R0+1.0 kpc, where R0 is the solar
Galactocentric distance. We build a model of the Galaxy including bulge, bar,
disc and halo components, which reproduces the observed specific features of
the velocity distribution in the Galactocentric distance interval |R-R0|< 1.5
kpc. The best agreement corresponds to the time 1.8+/-0.5 Gyr after the start
of the simulation. A model of the Galaxy with the bar rotating at the angular
velocity of Omega_b=55+/-3 km s-1 kpc-1, which sets the OLR of the bar at the
distance of R0-0.5+/-0.4 kpc, provides the best agreement between the model and
observed velocities. The position angle of the bar, theta_b, corresponding to
the best agreement between the model and observed velocities is theta_b=45+/-15
degrees.
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