J/MNRAS/489/3093 Gaia DR2 parallax of globular clusters (Shao+, 2019)
Gaia parallax of Milky Way globular clusters - A solution of mixture model.
Shao Z., Li L.
<Mon. Not. R. Astron. Soc., 489, 3093-3101 (2019)>
=2019MNRAS.489.3093S 2019MNRAS.489.3093S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Parallaxes, trigonometric
Keywords: parallaxes - globular clusters: general -
globular clusters: individual: M4 -
globular clusters: individual: NGC6397 -
globular clusters: individual: - omega Cen -
globular clusters: individual: 47 Tuc
Abstract:
We have established a mixture model approach to derive the parallax of
the MilkyWay globular clusters. It avoids the problem of cluster
membership determination and provides a completely independent
astrometrical solution by purely using the parallax data. This method
is validated with simulated clusters of Pancino et al.. We have
resolved 120 real globular clusters by the mixture model using
parallaxes of the second data release of Gaia. They construct the
largest direct parallax sample up to now. In comparison with other
direct parallax results based on cluster members, including 75
clusters of Gaia Collaboration, our method presents its accuracy,
especially for some particular clusters. A systematic offset of
-27.6±1.7 uas, together with a scatter of 22.8±1.3 uas is found in
comparison with other indirect parallax measurements. They are
consistent with the global value and the variation of the zero-point
of current Gaia parallaxes. Distances of several specific nearby
globular clusters are discussed while the closest ones can reach high
precisions, even taking the systematic error into account.
Description:
Parallaxes of 120 known Galactic globular clusters are derived
from Gaia DR2 with a mixture model.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 66 120 Fitting results of parallax of globular clusters
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/543/A156 : Milky Way global survey of star clusters (Kharchenko+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- ID Cluster ID
19- 29 A11 --- Name Cluster name
31- 41 A11 --- Range Selection of the fitting radius of a cluster (1)
43- 47 F5.2 arcmin Rad Fitting radius in arcmin
49- 54 I6 --- Ns Number of fitting stars
57- 61 F5.1 uas PlxC Parallax of the GC (2)
63- 66 F4.1 uas e_PlxC Fitting uncertainties of Parallax of the GC (3)
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Note (1): r_0 and r_1 are the visible radii of the core and the central parts
(Kharchenko et al. 2012A&A...543A.156K 2012A&A...543A.156K).
Note (2): PlxC is the apparent parallax of GC without the correction of
zero-point (-29uas).
Note (3): e_PlxC is the statistical error of PlxC, while a significant
systematic uncertainty should also be considered (∼25uas, see 4.2 for
details).
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Acknowledgements:
Zhengyi Shao, zyshao(at)shao.ac.cn
(End) Zhengyi Shao [Shanghai Astron. Obs.], Patricia Vannier [CDS] 20-Feb-2020