2010/03/12 by Ortwin Gerhard, Gerhard, Ortwin
Physics and Astronomy · #Advanced Mathematical Theories and Applications #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Scientific Research and Discoveries
paper · pdf · doi:10.48550/arxiv.1003.2489
openalex publication_date 2010/03/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A brief review is given of different methods used to determine the pattern speeds of the Galactic bar and spiral arms. The Galactic bar rotates rapidly, with corotation about halfway between the Galactic center and the Sun, and outer Lindblad resonance not far from the solar orbit, R0. The Galactic spiral arms currently rotate with a distinctly slower pattern speed, such that corotation is just outside R0. Both structures therefore seem dynamically decoupled.