J/MNRAS/505/5978 Gaia EDR3 view on Galactic globular clusters (Vasiliev+, 2021)
Gaia EDR3 view on Galactic globular clusters.
Vasiliev E., Baumgardt H.
<Mon. Not. R. Astron. Soc. 505, 5978-6002 (2021)>
=2021MNRAS.505.5978V 2021MNRAS.505.5978V (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, globular ; Proper motions
Keywords: parallaxes - proper motions - globular clusters: general -
Galaxy: kinematics and dynamics
Abstract:
We use the data from Gaia Early Data Release 3 (EDR3) to study the
kinematic properties of Milky Way globular clusters. We measure the
mean parallaxes and proper motions (PM) for 170 clusters, determine
the PM dispersion profiles for more than 100 clusters, uncover
rotation signatures in more than 20 objects, and find evidence for
radial or tangential PM anisotropy in a dozen richest clusters. At the
same time, we use the selection of cluster members to explore the
reliability and limitations of the Gaia catalogue itself. We find that
the formal uncertainties on parallax and PM are underestimated by
10-20% in dense central regions even for stars that pass numerous
quality filters. We explore the spatial covariance function of
systematic errors, and determine a lower limit on the uncertainty of
average parallaxes and PM at the level 0.01mas and 0.025mas/yr,
respectively. Finally, a comparison of mean parallaxes of clusters
with distances from various literature sources suggests that the
parallaxes for stars with G>13 (after applying the zero-point
correction suggested by Lindegren et al. (2021A&A...649A...4L 2021A&A...649A...4L) are
overestimated by ∼0.01±0.003mas. Despite these caveats, the quality
of Gaia astrometry has been significantly improved in EDR3 and
provides valuable insights into the properties of star clusters.
Description:
The catalogue of mean parallaxes and proper motions of 170 Milky Way
globular clusters, derived from the Gaia early data release 3
astrometry. The uncertainties take into account the spatially
correlated systematic errors in Gaia and are at the level 0.01mas for
parallaxes and 0.025mas/yr for proper motions for most clusters. The
catalogue of stars with membership probabilities is available at
https://zenodo.org/record/4549397, and the Python program for querying
the Gaia catalogue and determining the mean parallaxes and proper
motions and is provided at
https://github.com/GalacticDynamics-Oxford/GaiaTools
Catalogue supersedes the parallaxes and proper motions previously
derived from Gaia DR2 by both authors (J/MNRAS/482/5138,
J/MNRAS/484/2832)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 109 170 The catalogue of cluster proper motions
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/MNRAS/482/5138 : Galactic GC proper motions & velocities (Baumgardt+, 2019)
J/MNRAS/505/5957 : GC distances (Baumgardt & Vasiliev, 2021)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Common name, NGC identifier, etc.
13- 22 A10 --- OName Other name
25- 31 F7.3 deg RAdeg Right Ascension (J2000)
33- 39 F7.3 deg DEdeg Declination (J2000)
41- 47 F7.3 mas/yr pmRA Proper motion in right ascension, pmRA*cosDE
49- 55 F7.3 mas/yr e_pmRA Uncertainty (including systematic) in pmRA
57- 63 F7.3 mas/yr pmDE Proper motion in declination
65- 71 F7.3 mas/yr e_pmDE Uncertainty (including systematic) in pmDE
73- 79 F7.2 --- corr Correlation coefficient between uncertainties
81- 87 F7.3 mas plx Parallax
89- 95 F7.3 mas e_plx Uncertainty (including systematic) in plx
97-103 F7.2 arcmin Rscale Scale radius of Gaia-detected cluster members
105-109 I5 --- Nstar Number of Gaia-detected cluster member stars
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Acknowledgements:
Eugene Vasiliev, eugvas(at)lpi.ru
(End) E. Vasiliev [Inst. Astronomy, Cambridge, UK], P. Vannier [CDS] 13-Jul-2021