Vertical Structure and Kinematics of the Galactic Outer Disk

Abstract

We report measurements of parallax and proper motion for four 22 GHz water maser sources as part of VERA Outer Rotation Curve project. All sources show Galactic latitudes of $>$ 2${}^{\circ }$ and Galactocentric distances of $>$ 11 kpc at the Galactic longitude range of 95${}^{\circ }$ $<l<$ 126${}^{\circ }$. The sources trace the Galactic warp reaching to 200$\sim$400 pc, and indicate the signature of the warp to 600 pc toward the north Galactic pole. The new results along with previous results in the literature show the maximum height of the Galactic warp is increased with Galactocentric distance. Also, we examined velocities perpendicular to the disk for the sample, and found an oscillatory behavior between the vertical velocities and Galactic heights. This behavior suggests the existence of the bending (vertical density) waves, possibly induced by a perturbing satellite (e.g. passage of the Sagittarius dwarf galaxy).

arXiv commentAccepted for publication in PASJ; 4 figures & 6 tables

References in corpus (35)

• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
• 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
• Three Dimensional Structure of the Milky Way Disk
• Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
• The observed spiral structure of the Milky Way
• Old stellar Galactic disc in near-plane regions according to 2MASS: scales, cut-off, flare and warp
• The Sagittarius impact as an architect of spirality and outer rings in the Milky Way
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: II. The Molecular Gas Disk
• The Properties of Massive, Dense, Clumps: Mapping Surveys of HCN and CS
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: I. The HI Disk
• Vertical density waves in the Milky Way disc induced by the Sagittarius Dwarf Galaxy
• 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
• Fundamental Parameters of the Milky Way Galaxy Based on VLBI astrometry
• Trigonometric Parallaxes of 6.7 GHz Methanol Masers
• An intuitive 3D map of the Galactic warp's precession traced by classical Cepheids
• Three-Dimensional Distribution of the ISM in the Milky Way Galaxy: III. The Total Neutral Gas Disk
• Galactic Warps Induced By Cosmic Infall
• The Galactic warp revealed by Gaia DR2 kinematics
• Parallaxes of Star Forming Regions in the Outer Spiral Arm of the Milky Way
• The Bolocam Galactic Plane Survey. X. A Complete Spectroscopic Catalog of Dense Molecular Gas Observed toward 1.1 mm Dust Continuum Sources with 7.5 <= l <= 194 degrees
• Distance to NGC 281 in a Galactic Fragmenting Superbubble: Parallax Measurements with VERA
• Kinematics with Gaia DR2: The Force of a Dwarf
• Outer Rotation Curve of the Galaxy with VERA I: Trigonometric parallax of IRAS 05168+3634
• Mapping the Galactic disk with the LAMOST and Gaia Red clump sample. II. 3D asymmetrical kinematics of mono-age populations in the disk between 6$-14$ \,kpc
• First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259
• A Precise Distance to IRAS 00420+5530 via H2O Maser Parallax with the VLBA
• Parallaxes of 6.7-GHz Methanol Masers towards the G305.2 High-Mass Star Formation Region
• Parallaxes for star forming regions in the inner Perseus spiral arm
• Non-circular Motions in the Outer Perseus Spiral Arm
• Outer Rotation Curve of the Galaxy with VERA II: Annual Parallax and Proper Motion of the Star-Forming Region IRAS21379+5106
• Absolute Proper Motion of IRAS 00259+5625 with VERA : Indication of Superbubble Expansion Motion
• Outer rotation curve of the Galaxy with VERA IV: Astrometry of IRAS 01123+6430 and the possibility of cloud-cloud collision

Cited by in corpus (6)

• The First VERA Astrometry Catalog
• Precise radio astrometry and new developments for the next generation of instruments
• VERA astrometry toward the Perseus arm gap
• Parameters of the Galactic Spiral Density Wave from Masers with Parallax Errors Less Than 10%
• Study of the Galactic Rotation Based on Masers and Radio Stars with VLBI Measurements of Their Parallaxes
• EAVN Astrometry toward the Extreme Outer Galaxy: Kinematic distance with the proper motion of G034.84-00.95