Trigonometric Parallaxes of Four Star-forming Regions in the Distant Inner Galaxy

Abstract

We have measured trigonometric parallaxes for four water masers associated with distant massive young stars in the inner regions of the Galaxy using the VLBA as part of the BeSSeL Survey. G026.50$+$0.28. is located at the near end of the Galactic bar, perhaps at the origin of the Norma spiral arm. G020.77$-$0.05 is in the Galactic Center region and is likely associated with a far-side extension of the Scutum arm. G019.60$-$0.23 and G020.08$-$0.13 are likely associated and lie well past the Galactic Center. These sources appear to be in the Sagittarius spiral arm, but an association with the Perseus arm cannot be ruled out.

17 pages, 3 figures, 5 tables

References in corpus (10)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• ATLASGAL --- properties of a complete sample of Galactic clumps
• Water maser motions in W3(OH) and a determination of its distance
• Trigonometric parallaxes of star forming regions in the Sagittarius spiral arm
• Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm
• The local spiral structure of the Milky Way
• Trigonometric Parallaxes of Star Forming Regions in the Scutum Spiral Arm
• Anomalous peculiar motions of high-mass young stars in the Scutum spiral arm
• Trigonometric Parallaxes of Star Forming Regions Beyond the Tangent Point of the Sagittarius Spiral Arm

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• ALMA and VLBA views on the outflow associated with an O-type protostar in G26.50+0.28
• Signatures of simulated spiral arms on radial actions
• First detection of the $J_{-1}\to (J-$ 1)${}_0-E$ methanol maser transitions at $J=7$ and $10$
• Three Models of the Gravitational Potential of the Milky Way
• NH3 (1,1) hyperfine intensity anomalies in infall sources