N-body simulations in reconstruction of the kinematics of young stars in the Galaxy

Abstract

We try to determine the Galactic structure by comparing the observed and modeled velocities of OB-associations in the 3 kpc solar neighborhood. We made N-body simulations with a rotating stellar bar. The galactic disk in our model includes gas and stellar subsystems. The velocities of gas particles averaged over large time intervals ($\sim 8$ bar rotation periods) are compared with the observed velocities of the OB-associations. Our models reproduce the directions of the radial and azimuthal components of the observed residual velocities in the Perseus and Sagittarius regions and in the Local system. The mean difference between the model and observed velocities is $\Delta V=3.3$ km s${}^{-1}$. The optimal value of the solar position angle ${\theta }_b$ providing the best agreement between the model and observed velocities is ${\theta }_b=45\pm 5^{\circ }$, in good accordance with several recent estimates. The self-gravitating stellar subsystem forms a bar, an outer ring of subclass $R_1$, and slower spiral modes. Their combined gravitational perturbation leads to time-dependent morphology in the gas subsystem, which forms outer rings with elements of the $R_1$- and $R_2$-morphology. The success of N-body simulations in the Local System is likely due to the gravity of the stellar $R_1$-ring, which is omitted in models with analytical bars.

13 pages, 13 figures, accepted to Astronomy and Astrophysics

References in corpus (24)

• Validation of the new Hipparcos reduction
• Constraints from Dynamical Friction on the Dark Matter Content of Barred Galaxies
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• First GLIMPSE Results on the Stellar Structure of the Galaxy
• Spiral arms, bar shape and bulge microlensing in the Milky Way
• How Large Are the Bars in Barred Galaxies?
• Order and chaos in the local disc stellar kinematics induced by the Galactic bar
• Gas flow models in the Milky Way embedded bars
• The formation of spiral arms and rings in barred galaxies
• Rings and spirals in barred galaxies. I Building blocks
• A New Spiral Arm of the Galaxy: The Far 3-Kpc Arm
• Tracing the long bar with red-clump giants
• The properties of the Galactic bar implied by gas kinematics in the inner Milky Way
• Low-Velocity Streams in the Solar Neighborhood Caused by the Galactic Bar
• A New Model for the Spiral Structure of the Galaxy. Superposition of 2+4-armed patterns
• Model-based pattern speed estimates for 38 barred galaxies
• Kinematics of OB-associations and the new reduction of the Hipparcos data
• The long Galactic bar as seen by UKIDSS Galactic Plane Survey
• The distribution of maser stars in the inner Milky Way: the effect of a weak, rotating bar
• Kinematics of the outer pseudorings and the spiral structure of the Galaxy
• The Bar Pattern Speed of NGC 1433 Estimated Via Sticky-Particle Simulations
• Periodic Pattern in the Residual-Velocity Field of OB Associations
• Galactic Rotation Parameters from Data on Open Star Clusters
• Milky Way Gas Dynamics

Cited by in corpus (11)

• Kinematics of OB-associations in Gaia epoch
• Classical Cepheids in the Galactic outer ring R1R2'
• Two-component outer ring and the Galactic spiral structure
• Distance scale for high-luminosity stars in OB associations and in field with Gaia DR2. Spurious systematic motions
• Galactic resonance rings. Modelling of motions in the wide solar neighborhood
• Influence of the Galactic bar on the kinematics of the disc stars with Gaia EDR3 data
• Evidence of the Galactic outer ring R1R2' from young open clusters and OB-associations
• Massive Stellar Content of the Galactic Supershell GSH 305+01-24
• Straight segments in the galactic discs
• Galaxies with 'Rows': A New Catalog
• The R1R2' outer ring revealed by young open cluster data