J/MNRAS/511/4702 Membership probabilities of M 37 stars (Griggio+, 2022)
Astrometric star-cluster membership probability application to the case of M 37
with Gaia EDR3.
Griggio M., Bedin L.R.
<Mon. Not. R. Astron. Soc. 511, 4702-4709 (2022)>
=2022MNRAS.511.4702G 2022MNRAS.511.4702G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Models ; Parallaxes, trigonometric ;
Positional data
Keywords: astrometry -
(Galaxy:) open clusters and associations: individual:
NGC 2099 (M 37) - catalogues
Abstract:
In this work, starting from the well-accepted relations in literature,
we introduce a new formalism to compute the astrometric membership
probabilities for sources in star clusters, and we provide an
application to the case of the open cluster M 37. The novelty of our
approach is a refined - and magnitude- dependent - modelling of the
parallax distribution of the field stars. We employ the here-derived
list of members to estimate the cluster's mean systemic astrometric
parameters, which are based on the most recent Gaia's catalogue
(EDR3).
Description:
In this work, we discuss an improvement of the astrometric method
exploiting the Gaia astrometry to increase the separation between
cluster and field stars. Including parallaxes provides additional
information to estimate membership probabilities. In this work, we
take into account of the parallax distribution to we rewrite the
distribution function of cluster from classical approach. We
considered the open cluster M 37 (NGC 2099) as a test case for
this new formalism for the computation of the membership
probabilities. We downloaded a portion of the Gaia EDR3 catalogue
(Gaia Collaboration 2021A&A...649A...1G 2021A&A...649A...1G, Cat. I/350) centred on
M 37 (αc = 88.074 deg, δc = +32.545 deg; Cantat-Gaudin
& Anders 2020A&A...633A..99C 2020A&A...633A..99C, Cat. J/A+A/633/A99) with a radius of 1.5
deg, and we computed the Pmemb for each source both including and
neglecting the contribution from the Gaia parallaxes. We present our
results in the table.dat, (i.e see section 2, 3 and 4 for more
details).
Next as explicited in the section 5, we proceed to the most probable
cluster members selection procedure on Gaia EDR3 illustrated in the
section 5 Astrometric parameters of M 37. We then further restrict
this sample to the very best stars requiring astrometric data quality
cut-offs (e.g Pω > 99.5 and 13 ≤ G ≤ 15.4).
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
05 52 17.76 +32 32 42.0 M 37 = C 0549+325
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table.dat 26 308588 M 37 star's cluster with their Pmemb computed
with the formalism presented in this work
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See also:
J/ApJ/908/L5 : Color-magnitude diagram for ω Centauri (Soltis+, 2021)
J/A+A/493/959 : UBV(RI)cHalpha photometry in omega Cen (Bellini+, 2009)
J/A+A/484/609 : BVI photometry and proper motions in M67 (Yadav+, 2008)
J/ApJ/856/23 : BANYAN. XI. The BANYAN Σ algorithm (Gagne+, 2018)
J/A+A/618/A59 : Gaia DR2 confirmed new nearby open clusters
(Castro-Ginard+, 2018)
J/A+A/615/A49 : TGAS stars membership in 128 open clusters
(Cantat-Gaudin+, 2018)
J/A+AS/146/251 : Open clusters absolute proper motions. I. (Baumgardt+, 2000)
J/A+A/633/A99 : Gaia DR2 open clusters in the Milky Way. II
(Cantat-Gaudin+, 2020)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaEDR3 Gaia EDR3 source identifier (sourceID)
21- 26 F6.3 --- Pmemb Computed membership probability Pω
including the parallax distribution following
the equation 8 of the section 3 (P)
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 03-Feb-2025