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Gaia Data Release 2 : Kinematics of globular clusters and dwarf galaxies around the Milky Way

Helmi, A. ; Van Leeuwen, F. ; McMillan, P. J. LU orcid ; Massari, D. ; Antoja, T. ; Robin, A. C. ; Lindegren, L. LU orcid ; Bastian, U. ; Arenou, F. and Babusiaux, C. , et al. (2018) In Astronomy and Astrophysics 616.
Abstract


Context. 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 different 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... (More)


Context. 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 different 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 Milky Way 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 9.1
-2.6

+6.2
× 10
11
M
âŠ
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.

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author collaboration
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Astrometry, Galaxies: dwarf, Galaxy: kinematics and dynamics, Globular clusters: general, Local Group, Magellanic Clouds
in
Astronomy and Astrophysics
volume
616
article number
A12
publisher
EDP Sciences
external identifiers
  • scopus:85051852234
ISSN
0004-6361
DOI
10.1051/0004-6361/201832698
language
English
LU publication?
yes
id
3619e3a9-eac3-4adc-946a-be68a4140763
date added to LUP
2019-04-29 13:39:39
date last changed
2024-04-16 03:28:46
@article{3619e3a9-eac3-4adc-946a-be68a4140763,
  abstract     = {{<p><br>
                            Context. 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 different 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 Milky Way 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 9.1<br>
                            <sub>-2.6</sub><br>
                                                         <br>
                            <sup>+6.2</sup><br>
                             × 10<br>
                            <sup>11</sup><br>
                             M<br>
                            <sub>âŠ</sub><br>
                             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.<br>
                        </p>}},
  author       = {{Helmi, A. and Van Leeuwen, F. and McMillan, P. J. and Massari, D. and Antoja, T. and Robin, A. C. and Lindegren, L. and Bastian, U. and Arenou, F. and Babusiaux, C. and Biermann, M. and Breddels, M. A. and Hobbs, D. and Jordi, C. and Pancino, E. and Reylé, C. and Veljanoski, J. and Vallenari, A. and Prusti, T. and De Bruijne, J. H.J. and Bailer-Jones, C. A.L. and Evans, D. W. and Eyer, L. and Jansen, F. and Klioner, S. A. and Lammers, U. and Luri, X. and Mignard, F. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and Walton, N. A. and Cropper, M. and Drimmel, R. and Katz, D. and Lattanzi, M. G. and Bakker, J. and Cacciari, C. and Castañeda, J. and Chaoul, L. and Cheek, N. and De Angeli, F. and Fabricius, C. and Guerra, R. and Holl, B. and Davidson, M. and Michalik, D. and Zwitter, T.}},
  issn         = {{0004-6361}},
  keywords     = {{Astrometry; Galaxies: dwarf; Galaxy: kinematics and dynamics; Globular clusters: general; Local Group; Magellanic Clouds}},
  language     = {{eng}},
  month        = {{08}},
  publisher    = {{EDP Sciences}},
  series       = {{Astronomy and Astrophysics}},
  title        = {{Gaia Data Release 2 : Kinematics of globular clusters and dwarf galaxies around the Milky Way}},
  url          = {{http://dx.doi.org/10.1051/0004-6361/201832698}},
  doi          = {{10.1051/0004-6361/201832698}},
  volume       = {{616}},
  year         = {{2018}},
}