期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 487, 期 4, 页码 5188-5208出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stz1630
关键词
Galaxy: bulge; Galaxy: kinematics and dynamics; Galaxy: structure; Galaxy: centre
资金
- Science and Technology Facilities Council, Cambridge
- Leverhulme Trust, Cambridge
- Newton Trust, Cambridge
- Christ's College, Cambridge
- National Science Foundation [NSF PHY-1748958]
- Science & Technology Facilities Council (STFC)
- European Research Council (ERC)
- ESO Telescopes at the La Silla or Paranal Observatories [179. B-2002]
- National Aeronautics and Space Administration
- National Science Foundation
- Alfred P. Sloan Foundation
- U.S. Department of Energy Office of Science
- Center for High-Performance Computing at the University of Utah
- Brazilian Participation Group
- Carnegie Institution for Science, Carnegie Mellon University
- Chilean Participation Group
- French Participation Group
- Harvard-Smithsonian Center for Astrophysics
- Instituto de Astrofisica de Canarias
- Johns Hopkins University
- Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo
- Korean Participation Group
- Lawrence Berkeley National Laboratory
- Leibniz Institut fur Astrophysik Potsdam (AIP)
- Max-Planck-Institut fur Astronomie (MPIA Heidelberg)
- Max-Planck-Institut fur Astrophysik (MPAGarching)
- Max-Planck-Institut fur Extraterrestrische Physik (MPE)
- National Astronomical Observatories of China
- New Mexico State University
- New York University
- University of Notre Dame
- Observatario Nacional / MCTI
- Ohio State University
- Pennsylvania State University
- Shanghai Astronomical Observatory
- United Kingdom Participation Group
- Universidad Nacional Autonoma de Mexico
- University of Arizona
- University of Colorado Boulder
- University of Oxford
- University of Portsmouth
- University of Utah
- University of Virginia
- University of Washington
- University of Wisconsin
- Vanderbilt University
- Yale University
- STFC [ST/S000623/1, ST/M001008/1, ST/R000905/1] Funding Source: UKRI
We analyse the kinematics of the Galactic bar-bulge using proper motions from the ESO public survey Vista Variables in the Via Lactea (VVV) and the second Gaia data release. Gaia has provided some of the first absolute proper motions within the bulge and the near-infrared VVV multi-epoch catalogue complements Gaia in highly extincted low-latitude regions. We discuss the relative-to-absolute calibration of the VVV proper motions using Gaia. Along lines of sight spanning and , we probabilistically model the density and velocity distributions as a function of distance of similar to 45 million stars. The transverse velocities confirm the rotation signature of the bar seen in spectroscopic surveys. The differential rotation between the double peaks of the magnitude distribution confirms the X-shaped nature of the bar-bulge. Both transverse velocity components increase smoothly along the near side of the bar towards the Galactic Centre, peak at the Galactic Centre, and decline on the far side. The anisotropy is sigma(l)/sigma(b) approximate to 1.1-1.3 within the bulk of the bar, reducing to 0.9-1.1 when rotational broadening is accounted for, and exhibits a clear X-shaped signature. The vertex deviation in l and b is significant |rho(lb)| less than or similar to 0.2, greater on the near side of the bar and produces a quadrupole signature across the bulge indicating approximate radial alignment. We have re-constructed the 3D kinematics from the assumption of triaxiality, finding good agreement with spectroscopic survey results. In the co-rotating frame, we find evidence of bar-supporting x1 orbits and tangential bias in the in-plane dispersion field.
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