Kinematics of the Milky way from the statistical analysis of the Gaia Data Release 3

Abstract

The aim of the analysis of data from the Gaia Space Observatory is to obtain kinematic parameters of the collective motion of stars in a part of our galaxy. This research is based on a statistical analysis of the motion of {$55,038,539$} stars selected in different directions from the Sun up to a distance of 3--6 kpc. We developed statistical methods for the analysis working with input data represented by the full astrometric solution (five parameters). Using the proposed statistical methods, we obtained the local velocity of the Sun $\left( U_{\odot}% ,V_{\odot},W_{\odot}\right) =(9.58,16.25,7.33)\pm(0.05,0.04,0.02)_{stat}% \pm(0.7,0.9,0.1)_{syst}$ km/s and the rotation velocity of the galaxy at different radii. For the Sun's orbit radius, we obtained the velocity of the galaxy rotation$V_c\approx 234\pm 4$ km/s. Collective rotation slows down in the region under study linearly with distance from the disk plane: $\Delta V/\Delta Z\cong 33.5{\mathrm{km}\mathrm{s}}^{-1}{\mathrm{kpc}}^{-1}$. We showed that the different kinematic characteristics and distributions, which depend on the position in the galaxy, can be well described in the studied 3D region by a simple Monte Carlo simulation model, representing an axisymmetric approximation of the galaxy kinematics. The optimal values of the six free parameters were tuned by comparison with the data.

21 pages, 19 figures, 3 tables

References in corpus (16)

• Gaia Data Release 3: Summary of the content and survey properties
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way
• Gaia Early Data Release 3: The Galactic anticentre
• The power spectrum of the Milky Way: Velocity fluctuations in the Galactic disk
• Mapping the Milky Way Disk with Gaia DR3: 3D extended kinematic maps and rotation curve to $\approx 30$ kpc
• The stellar velocity distribution function in the Milky Way galaxy
• Kinematic structures of the Solar neighbourhood revealed by Gaia DR1/TGAS and RAVE
• The Milky Way's circular velocity curve and its constraint on the Galactic mass with RR Lyrae stars
• The peculiar in-plane velocities in the outer disc of the Milky Way
• Gaia-DR2 extended kinematical maps. Part III: Rotation curves analysis, dark matter, and Modified Newtonian dynamics tests
• Which Milky Way masses are consistent with the slightly declining 5-25 kpc rotation curve?
• The intricate Galaxy disk: velocity asymmetries in Gaia-TGAS
• New stellar velocity substructures from Gaia DR3 proper motions
• Asymmetric Drift Map of the Milky Way disk Populations between 8$-$16 kpc with LAMOST and Gaia datasets