Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way
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Authors
Collaboration, Gaia
Helmi, A
Leeuwen, F van
McMillan, PJ
Massari, D
Antoja, T
Robin, A
Lindegren, L
Bastian, U
co-authors,
Journal Title
Astronomy & Astrophysics
ISSN
0004-6361
Publisher
EDP Sciences
Volume
616
Number
A12
Type
Article
Metadata
Show full item recordCitation
Collaboration, G., Helmi, A., Leeuwen, F. v., McMillan, P., Massari, D., Antoja, T., Robin, A., et al. (2018). Gaia Data Release 2: Kinematics of globular clusters and dwarf galaxies around the Milky Way. Astronomy & Astrophysics, 616 (A12)https://doi.org/10.1051/0004-6361/201832698
Abstract
Aims. The goal of this paper is to demonstrate the outstanding quality of the second data release of the Gaia mission and its power for constraining many di erent aspects of the dynamics of the satellites of the Milky Way. We focus here on determining the proper motions of 75 Galactic globular clusters, nine dwarf spheroidal galaxies, one ultra-faint system, and the Large and Small Magellanic Clouds.
Methods. Using data extracted from the Gaia archive, we derived the proper motions and parallaxes for these systems, as well as their uncertainties. We demonstrate that the errors, statistical and systematic, are relatively well understood. We integrated the orbits of these objects in three different Galactic potentials, and characterised their properties. We present the derived proper motions, space velocities, and characteristic orbital parameters in various tables to facilitate their use by the astronomical community.
Results. Our limited and straightforward analyses have allowed us for example to (i) determine absolute and very precise proper
motions for globular clusters; (ii) detect clear rotation signatures in the proper motions of at least five globular clusters; (iii) show that
the satellites of the MilkyWay are all on high-inclination orbits, but that they do not share a single plane of motion; (iv) derive a lower
limit for the mass of the Milky Way of 9:8$^{+6:7}_{2:7}$ x 10$6{11}$$\odot$ based on the assumption that the Leo I dwarf spheroidal is bound; (v) derive a rotation curve for the Large Magellanic Cloud based solely on proper motions that is competitive with line-of-sight velocity curves, now using many orders of magnitude more sources; and (vi) unveil the dynamical effect of the bar on the motions of stars in the Large Magellanic Cloud.
Conclusions. All these results highlight the incredible power of the Gaia astrometric mission, and in particular of its second data release.
Keywords
Galaxy: kinematics and dynamics, Galaxy: halo, Magellanic Clouds, globular clusters: general, galaxies: dwarf, Local Group, methods: data analysis, astrometry
Sponsorship
Includes STFC and ERC.
Funder references
STFC (ST/K000756/1)
STFC (ST/L006553/1)
STFC (ST/N000641/1)
STFC (PP/D006546/1)
STFC (ST/I000542/1)
STFC (ST/J005045/1)
PPARC (PP/C000757/1)
STFC (ST/P000975/1)
STFC (ST/S000089/1)
Embargo Lift Date
2100-01-01
Identifiers
External DOI: https://doi.org/10.1051/0004-6361/201832698
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280731
Rights
Licence:
http://www.rioxx.net/licenses/all-rights-reserved