2014/12/26 by Kazuya Hachisuka, K. Hachisuka, Y. K. Choi +6 · 66 citations
Physics and Astronomy · #Active galactic nucleus #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Disc #Galactic Center #Galactic astronomy #Galactic plane #Galaxy #Galaxy formation and evolution #Galaxy rotation curve #Geometry #Maser #Milky Way #Physics #Proper motion #Rotation (mathematics) #Spiral (railway) #Spiral galaxy #Stars #Stellar, planetary, and galactic studies #Very Long Baseline Array #astro-ph.GA
paper · pdf · doi:10.1088/0004-637x/800/1/2
published in The Astrophysical Journal 800(1), 2 (IOP Publishing) · 19 pages, 7 figures, Accepted for publication in ApJ
arxiv created 2014/12/26 · openalex publication_date 2015/02/02 · arxiv updated 2015/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We report parallaxes and proper motions of three water maser sources in high-mass star-forming regions in the Outer Spiral Arm of the Milky Way. The observations were conducted with the Very Long Baseline Array as part of Bar and Spiral Structure Legacy Survey and double the number of such measurements in the literature. The Outer Arm has a pitch angle of 14 9 ± 2 7 and a Galactocentric distance of 14.1 ± 0.6 kpc toward the Galactic anticenter. The average motion of these sources toward the Galactic center is 10.7 ± 2.1 km s −1 and we see no sign of a significant fall in the rotation curve out to 15 kpc from the Galactic center. The three-dimensional locations of these star-forming regions are consistent with a Galactic warp of several hundred parsecs from the plane.