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Title: Trigonometric parallaxes to star-forming regions within 4 kpc of the galactic center

We report four trigonometric parallaxes for high-mass star-forming regions within 4 kpc of the Galactic center. These measurements were made with the Very Long Baseline Array as part of the BeSSeL Survey. By associating these sources kinematically with large-scale features in CO and H I longitude-velocity diagrams, we begin to outline some major features of the inner Milky Way: the Connecting arm, the near and far 3 kpc arms, and the Norma arm. The Connecting arm in the first Galactic quadrant lies closer to the Galactic center than the far 3 kpc arm and is offset by the long-bar's major axis near its leading edge, supporting the presence of an inner Lindblad resonance. Assuming the 3 kpc arms are a continuous physical structure, the relative Galactocentric distance of its near and far sides suggests highly elliptical streamlines of gas around the bar(s) and a bar corotation radius, r {sub CR} ≳ 3.6 kpc. At a Galactic longitude near 10° and a heliocentric distance of about 5 kpc, the near 3 kpc arm and the Norma arm intersect on a face-on view of our Galaxy, while passing at different Galactic latitudes. We provide an accurate distance measurement to the W 31more » star-forming complex of 4.95{sub −0.43}{sup +0.51} kpc from the Sun, which associates it with a bright CO feature belonging to the near 3 kpc arm.« less
Authors:
; ; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)
  2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  3. INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)
Publication Date:
OSTI Identifier:
22348092
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 781; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; DISTANCE; GALAXY NUCLEI; MASERS; MASS; MILKY WAY; RESOLUTION; SUN; VELOCITY