Shanghai Jiaotong University Shen Juntai's team revealed the distribution of matter in the Milky Way with a gas dynamic model

Recently, the group of Professor Juntai Shen from the School of Physics and Astronomy of Shanghai Jiao Tong University has made important progress in the study of the structure of the Milky Way

As the galaxy where our solar system is located, the Milky Way has an irreplaceable position in understanding the formation and evolution of galaxies

Why do you need a gas dynamics model?

Although the Gaia satellite has measured the distances of nearly a billion stars to map the Milky Way in recent years, its detection of the disk structure is limited by the dust blocking of the optical band and the distances of distant stars (especially on the other side of the galactic center) measurement uncertainty

Based on this idea, the research team combined the results of the latest stellar dynamics model to test the gas motion under nearly a hundred different galactic potential fields, and finally obtained the model that best matches the observed results (Figure 1)

Figure 1 The best gas dynamics model for the Milky Way in the paper

Ordinary and special galaxy

An interesting question is "Is the Milky Way a typical barred spiral galaxy?" This concerns whether our conclusions about the Milky Way are universal

Figure 2 Comparison of the Milky Way and two extragalactic barred spiral galaxies

Comparison with mainstream cosmological simulations

The research team has given the most accurate rotation curve (which directly traces the mass distribution) of the Milky Way from the center of 100 parsecs to the vicinity of the sun based on the gas dynamics model

Fig.

The first author of the paper is Li Zhi, a postdoctoral fellow in the research group, and the corresponding author is Professor Shen Juntai

Paper link :

“Gas Dynamics in the Galaxy: Total Mass Distribution and the Bar Pattern Speed” Li, Shen*, Gerhard & Clarke, 2022, ApJ, 925 71