Unlocking the Secrets of the Stellar Halo: Dynamical Streams and the Galactic Bar
This study explores moving groups of stars in the Milky Way’s halo, revealing two streams influenced by the galaxy’s central bar. Using Gaia data and simulations, the authors show that these streams result from resonances with the bar’s rotation. By analyzing their motion, they estimate the Milky Way’s mass and bar pattern speed, refining our understanding of the galaxy’s structure and dynamics. Their findings highlight the role of resonances in shaping stellar motions.
How Globular Clusters Shape the Streams of Stars in the Milky Way
The paper explores how interactions with globular clusters, not just dark matter, create gaps in stellar streams like those of Palomar 5. Simulations show that close encounters with clusters like NGC 2808 can cause these gaps, complicating efforts to study dark matter using streams. This reveals the role of globular clusters in shaping galactic structures.
Unraveling the GD-1 Stream and Its Mysterious Cocoon: A DESI Perspective
The study by Valluri et al. uses DESI data to confirm a cocoon surrounding the GD-1 stellar stream—a broader, kinematically hotter structure with a common origin. Possible explanations include pre-accretion stripping, debris from a parent galaxy, interactions with dark matter subhalos, or perturbations from the Sagittarius dwarf galaxy. Future DESI observations will help determine the cocoon’s origin, providing insights into the Milky Way’s evolution and dark matter structure.