Lunch talk on Dec. 18, 2023

Gas Dynamics and the Gravitational Potential of the Milky Way

Speaker:Zhi Li (Shanghai Normal University)

Venue:Video Conference

Time:12:30 PM, Monday, Dec. 18, 2023

Abstract:

Gas morphology and kinematics in the Milky Way contain key information for understanding the formation and evolution of our Galaxy. In this talk, I will present a few hydrodynamical simulations based on realistic barred Milky Way potentials constrained by recent observations. Our model can reproduce most features in the observed longitude–velocity diagram, including the Central Molecular Zone, the Near and Far 3 kpc arms, the Molecular Ring, and the spiral arm tangents. It can also explain the noncircular motions of masers from the recent BeSSeL survey. The central gas kinematics are consistent with a mass of 6.9 × 10^8 Msun in the Nuclear Stellar Disk. In Particular, the gas kinematics in the center of the Milky Way is also a nature probe to test the predictions of the Fuzzy Dark Matter theory. Our model predicts the formation of an elliptical gaseous ring surrounding the bar, which is composed of the 3 kpc arms, the Norma arm, and the bar-spiral interfaces. This ring is similar to those “inner” rings in some Milky Way analogs with a boxy/peanut-shaped bulge (e.g., NGC 4565 and NGC 5746). The kinematics of gas near the solar neighborhood are governed by the Local arm. The bar pattern speed constrained by our gas model is 37.5–40 km/s/kpc, corresponding to a corotation radius of R_CR = 6.0–6.4 kpc. The rotation curve of our model rises gently within the central ∼ 5 kpc, significantly less steep than those predicted by some recent zoom-in cosmological simulations.

Report PPT:SWIFAR_Zhi Li.pptx