Parallaxes of Star Forming Regions in the Outer Spiral Arm of the Milky Way

Abstract

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 deg 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 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.

19 pages, 7 figures, Accepted for publication in ApJ

References in corpus (7)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The observed spiral structure of the Milky Way
• The Vertical Structure of the Outer Milky Way HI Disk
• Dark matter in the Milky Way, II. the HI gas distribution as a tracer of the gravitational potential
• Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm
• The Edge of the Milky Way Stellar Disk Revealed Using Clump Giant Stars as Distance Indicators
• Distance and proper motion measurement of water masers in Shapless 269 IRS 2w

Cited by in corpus (21)

• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• The First VERA Astrometry Catalog
• Precise radio astrometry and new developments for the next generation of instruments
• Radio continuum and polarization study of SNR G57.2+0.8 associated with magnetar SGR1935+2154
• On the detection of Exomoons: A search in Kepler data for the orbital sampling effect and the scatter peak
• Metallicity Structure in the Milky Way Disk Revealed by Galactic HII Regions
• A guided map to the Spiral arms in the galactic disk of the Milky Way
• Anomalous peculiar motions of high-mass young stars in the Scutum spiral arm
• The Forgotten Quadrant Survey. ${}^{12}$CO and ${}^{13}$CO (1-0) survey of the Galactic Plane in the range 220°$<l<$240° -2.5°$<b<$0°
• Constraining the pitch angle of the Galactic spiral arms in the Milky Way
• A 6.7 GHz Methanol Maser Survey at High Galactic Latitudes
• Magnetic field evolution and reversals in spiral galaxies
• Streaming Motions and Kinematic Distances to Molecular Clouds
• Resolving the distance controversy for Sharpless 269: A possible kink in the outer arm
• Vertical Structure and Kinematics of the Galactic Outer Disk
• Spatial and velocity offsets of Galactic masers from the centers of spiral arms
• Star formation activity beyond the outer Arm I: WISE-selected candidate star-forming regions
• Interarm islands in the Milky Way -- the one near the Cygnus spiral arm
• Distances of Galactic Radio Pulsars; First Quadrant: $-2^{\circ }<\ell <90^{\circ }$ and $-2^{\circ }<b<2^{\circ }$
• CHEMOUT: CHEMical complexity in star-forming regions of the OUTer Galaxy. V. Chemical composition gradients as a function of the galactocentric radius
• The distances of 61 PGCCs in the Second Galactic Quadrant