Wu, Y. W.Y. W.WuReid, M. J.M. J.ReidSakai, N.N.SakaiDame, T. M.T. M.DameMenten, K. M.K. M.MentenBrunthaler, A.A.BrunthalerXu, Y.Y.XuLi, J. J.J. J.LiHo, B.B.HoZhang, B.B.ZhangRYGL, Kazi Lucie JessicaKazi Lucie JessicaRYGLZheng, X. W.X. W.Zheng2021-02-162021-02-1620190004-637Xhttp://hdl.handle.net/20.500.12386/30411As part of the BeSSeL Survey, we report trigonometric parallaxes and proper motions of molecular maser sources associated with 13 distant high-mass star-forming regions in the Sagittarius spiral arm of the Milky Way. In particular, we obtain improved parallax distance estimates for three well-studied regions: {1.9}<SUB>-0.1</SUB><SUP>+0.1</SUP> {kpc} for M17, {5.3}<SUB>-0.9</SUB><SUP>+1.3</SUP> {kpc} for W51, and {7.9}<SUB>-0.7</SUB><SUP>+0.9</SUP> {kpc} for GAL 045.5+00.0. Peculiar motions for all but one source are less than 20 km s<SUP>-1</SUP>. We fit a log-periodic spiral to the locations and estimate an average pitch angle of 7.°2 ± 1.°9. We find that the section of the arm beyond the tangent point in the first quadrant of the Milky Way appears 15 pc below the IAU-defined Galactic plane.STAMPAenArticle10.3847/1538-4357/ab001a2-s2.0-85064437835000462738400012https://iopscience.iop.org/article/10.3847/1538-4357/ab001a2019ApJ...874...94WFIS/05 - ASTRONOMIA E ASTROFISICA