Spiraling into Control: Spiral Density Wave Structure of GAIA DR2 Galactic Radial Velocities

Chase Fuller


The goals of this study, awaiting future work, are to (1) determine the sturdiness of the galactic models and (2) learn about the spiral density wave parameters unique to the Milky Way. The second data release from the Gaia Mission contains approximately 7.2 million stars with measured line-of-sight velocities. After requiring statistically robust data, we transformed the surviving sources from International Celestial Reference Frame coordinates (p, α, δ) to galactocentric coordinates (R, θ, z) and binned as a function of galactic radius. The mean galactic radial velocities of each bin ⟨VR⟩obs and associated errors σobs were calculated. We then presented a method for fitting spiral density wave theory predictions of mean radial velocities ⟨VR⟩mod to the observed values using models of the Milky Way.