When a Bar Tricks the Eye: How Streaming Gas Motions Imitate a Bulge in the Milky Way
Junichi Baba’s study shows that gas motions in the Milky Way’s inner regions are strongly influenced by the central bar, creating non-circular streaming that mimics a massive bulge. Using simulations, he demonstrates that the steep rise in the inner rotation curve can be explained without extra mass, cautioning against overestimating the Galaxy’s central mass from gas-based methods alone.
Spinning Stars and Galactic Clues: How Stellar Motions Reveal the History of Our Galaxy's Bulge
This study explores how stars move in the Milky Way’s bulge using simulations and observations. It finds that younger, metal-rich stars show strong movement patterns shaped by the galaxy’s central bar, while older, metal-poor stars do not. The results support the idea that the bulge formed mainly through internal processes, not galaxy mergers.
Exploring the Heart of the Milky Way: A Study of Its Bulge Structure, Kinematics, and Stars
This study explores the Milky Way’s bulge using OGLE, APOGEE, and Gaia data, focusing on its structure, stellar populations, and dynamics. Researchers identified distinct central and inner bulge star groups, with the inner aligning with the Galactic bar and the central showing slower rotation. Chemical analyses revealed differences in star formation histories. A boxy bulge shape was supported over an X-shaped structure, highlighting the bulge's complex evolution from the Galactic disk.
Tracing the Origins of the Milky Way's Bulge
Tristan Boin et al. investigate puzzling velocity trends in the Milky Way’s bulge, where metal-rich stars exhibit high velocity dispersion near the midplane, reversing at higher latitudes. Using APOGEE data and N-body simulations, they show that the bulge's bar-like structure traps metal-rich, thin-disk stars more efficiently. This study reinforces the idea that the bulge forms from disk material rather than a classical spheroid.