J/ApJ/923/129 Membership for open clusters with Gaia DR2 (Jaehnig+, 2021)
Membership lists for 431 open clusters in Gaia DR2 using extreme deconvolution
Gaussian mixture models.
Jaehnig K., Bird J., Holley-Bockelmann K.
<Astrophys. J., 923, 129 (2021)>
=2021ApJ...923..129J 2021ApJ...923..129J
ADC_Keywords: Clusters, open; Proper motions; Parallaxes, trigonometric;
Reddening; Photometry; Colors; Optical; Stars, distances
Keywords: Astronomy data analysis ; Open star clusters ; Astrometry
Abstract:
Open clusters are groups of stars that form at the same time, making
them an ideal laboratory to test theories of star formation, stellar
evolution, and dynamics in the Milky Way disk. However, the utility of
an open cluster can be limited by the accuracy and completeness of its
known members. Here, we employ a "top-down" technique, Extreme
Deconvolution Gaussian Mixture Models (XDGMMs), to extract and
evaluate known open clusters from Gaia DR2 by fitting the distribution
of stellar parallax and proper motion along a line of sight. Extreme
deconvolution techniques can recover the intrinsic distribution of
astrometric quantities, accounting for the full covariance matrix of
the errors; this allows open cluster members to be identified even
when presented with relatively uncertain measurement data. To date,
open cluster studies have only applied extreme deconvolution to
specialized searches for individual systems. We use XDGMMs to
characterize the open clusters reported by
Ahumada & Lapasset (2007A&A...463..789A 2007A&A...463..789A) and are able to recover
420 of the 426 open clusters therein (98.1%). Our membership list
contains the overwhelming majority (>95%) of previously known cluster
members. We also identify a new, significant, and relatively faint
cluster member population and validate their membership status using
Gaia eDR3. We report the fortuitous discovery of 11 new open cluster
candidates within the lines of sight we analyzed. We present our
technique, as well as its advantages and challenges, and publish our
membership lists and updated cluster parameters.
Description:
We first assemble a list of open clusters (OCs) to consider using the
cluster catalog from Ahumada & Lapasset (2007, J/A+A/463/789).
We searched for all Gaia DR2 (I/345) sources within the 426 target
fields of view. In addition to the Gaia DR2 data, we collected all
previous distance determinations to the clusters in our sample through
the SIMBAD database. See Section 2.
Ultimately, we identify a cluster and its members via an Extreme
Deconvolution Gaussian Mixture Model (XDGMM) fit of the density field.
See Section 3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 202 431 Cluster parameters for 420 open clusters confirmed
in this work and 11 newly discovered open clusters
table2.dat 294 172584 Individual membership measurements
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+AS/141/371 : Low-mass stars evolutionary tracks (Girardi+, 2000)
J/A+A/463/789 : Blue stragglers in open clusters (Ahumada+, 2007)
J/ApJS/194/9 : X-ray star clusters in the Carina complex (Feigelson+, 2011)
J/A+A/564/A79 : Proper motions of open clusters from UCAC4 (Dias+, 2014)
J/ApJ/787/107 : Spatial structure of young stellar cl. I. (Kuhn+, 2014)
J/AJ/154/87 : Stellar pop. of the young star cluster NGC6231 (Kuhn+, 2017)
J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)
J/A+A/615/A49 : TGAS star membership in open clusters (Cantat-Gaudin+, 2018)
J/A+A/618/A59 : GaiaDR2 confirmed new nearby open cl. (Castro-Ginard+, 2018)
J/MNRAS/478/5184 : UCAC5 open clusters membership and PM (Dias+, 2018)
J/AJ/156/121 : Likely open cluster NGC 6405 members (Gao, 2018)
J/MNRAS/480/5242 : (non-)existence of five sparse open clusters (Kos+, 2018)
J/A+A/624/A8 : Evolved Gal. open cl. dynamical properties (Angelo+, 2019)
J/A+A/623/A108 : Age of 269 GDR2 open clusters (Bossini+, 2019)
J/A+A/624/A126 : New open cl. in Perseus direction (Cantat-Gaudin+, 2019)
J/A+A/627/A35 : New open cl. in Galactic anti-centre (Castro-Ginard+, 2019)
J/ApJS/245/32 : Newly identified star clusters in Gaia DR2 (Liu+, 2019)
J/A+A/625/A115 : Ruprecht 147 DANCe. I. (Olivares+, 2019)
J/ApJ/887/19 : Gaia stars in Price-Whelan 1 (Price-Whelan+, 2019)
J/A+A/633/A99 : Gaia DR2 open clusters in the MW. II (Cantat-Gaudin+, 2020)
J/A+A/640/A1 : Portrait Galactic disc (Cantat-Gaudin+, 2020)
J/A+A/635/A45 : Open clusters in the Galactic disc (Castro-Ginard+, 2020)
J/MNRAS/496/2021 : New Galactic open clusters (Ferreira+, 2020)
J/AJ/160/279 : Untangling the Galaxy. II. Within 3kpc (Kounkel+, 2020)
J/A+A/646/A104 : Improving the open cluster census. I. (Hunt+, 2021)
J/ApJ/912/162 : Open clusters in solar neighborhood (Pang+, 2021)
J/MNRAS/503/3279 : GALAH survey. Gal. disc with open clusters (Spina+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Cl Cluster Name (1)
18- 24 F7.3 deg RAdeg Central (weighted median), cluster Right
Ascension (ICRS)
26- 30 F5.3 deg e_RAdeg [0/1.7] Median absolute deviation in RAdeg
32- 38 F7.3 deg DEdeg [-68.4/85.3] Central (weighted median),
cluster Declination (ICRS)
40- 44 F5.3 deg e_DEdeg [0/1.1] Median absolute deviation in DEdeg
46- 51 F6.3 mas plx [0.04/21.4] Weighted median parallax
(Gaia DR2-based)
53- 57 F5.3 mas e_plx [0.002/0.5] Median absolute deviation in plx
59- 65 F7.3 mas/yr pmRA [-36/107] Weighted median proper motion in RA
(Gaia DR2-based)
67- 71 F5.3 mas/yr e_pmRA [0.001/5.4] Median absolute deviation in pmRA
73- 79 F7.3 mas/yr pmDE [-46/24] Weighted median proper motion in DE
(Gaia DR2-based)
81- 85 F5.3 mas/yr e_pmDE [0.002/0.7] Median absolute deviation in pmDE
87- 92 F6.3 deg r50 [0.01/54.1] Radius containing 1/2 cluster
members
94- 97 I4 --- N85 [19/6668] Number of members with Pmemb
(Table2) >85%
99-104 F6.3 kpc dmode05 [0.047/13.1] 05th percentile, distance
posterior distribution
106-111 F6.3 kpc dmode16 [0.047/13.5] 16th percentile, distance
posterior distribution
113-118 F6.3 kpc dmode [0.047/14.7] 50th percentile, distance
posterior distribution
120-125 F6.3 kpc dmode84 [0.047/15.9] 84th percentile, distance
posterior distribution
127-132 F6.3 kpc dmode95 [0.047/16.3] 95th percentile, distance
posterior distribution
134-140 F7.3 kpc Xgc [-22.1/0.7] Galactic coordinate, X
142-147 F6.3 kpc Ygc [-8.9/7.4] Galactic coordinate, Y
149-154 F6.3 kpc Zgc [-4.2/2.2] Galactic coordinate, Z, height
from plane
156-161 F6.3 kpc Rgc [5.1/22.6] Galactic coordinate, R, radius
163-167 F5.3 [yr] logAge [7.2/8.6]? Auriga Neural Net-based Age (1)
169-173 F5.3 [yr] e_logAge [0.07/0.4]? Uncertainty in logAge (1)
175-182 F8.3 pc Dist [460/2892]? Auriga Neural Net-based distance (1)
184-190 F7.3 pc e_Dist [10/145]? Uncertainty in Dist (1)
192-196 F5.3 mag Avmag [0.2/4]? Auriga Neural Net-based V-band
reddening (1)
198-202 F5.3 mag e_Avmag [0.04/0.3]? Uncertainty in Avmag (1)
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Note (1): Eleven newly discovered open clusters are provided with cluster names
XDOCC ##. Age, distance and reddening parameters from Auriga Neural Net
modeling are provided for these new clusters.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Cl Cluster Name (1)
18- 36 I19 --- Gaia Gaia DR2 unique source id
38- 61 F24.20 deg RAdeg Gaia DR2 Right Ascension (ICRS) at Epoch=2015.5
63- 82 F20.18 deg e_RAdeg [0.008/1.1] Standard error in RAdeg
84- 107 F24.20 deg DEdeg [-69/86.1] Gaia DR2 Declination (ICRS) at
Epoch=2015.5
109- 128 F20.18 deg e_DEdeg [0.007/1] Standard error in DEdeg
130- 152 E23.13 mas plx [-3.5/22.7] Gaia DR2 absolute stellar parallax
154- 173 F20.18 mas e_plx [0.01/1.1] Standard error of parallax
175- 197 E23.13 mas/yr pmRA [-39/124] Gaia DR2 proper motion in right
ascension direction (pmRA*cosDE)
199- 218 F20.18 mas/yr e_pmRA [0.01/2.1] Standard error of pmRA
220- 242 E23.13 mas/yr pmDE [-50/27] Gaia DR2 proper motion in declination
244- 263 F20.18 mas/yr e_pmDE [0.01/2.1] Standard error of pmDE
265- 274 F10.7 mag Gmag [3.28/18] Gaia DR2 G-band mean magnitude (Vega)
276- 289 E14.8 mag Bp-Rp [-2.8/7]? Gaia DR2 BP-RP color index
291- 294 F4.2 --- Pmem [0.5/1] Membership probability
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Note (1): Membership for eleven newly discovered open clusters are provided
with cluster names XDOCC ##.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-May-2023