J/MNRAS/534/3654 Membership of variable stars in Galactic GC (Prudil+, 2024)
On the membership of variable stars in Galactic globular clusters:
the Oosterhoff gap.
Prudil Z., Arellano Ferro A.
<Mon. Not. R. Astron. Soc. 534, 3654-3664 (2024)>
=2024MNRAS.534.3654P 2024MNRAS.534.3654P (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Stars, variable ; Optical
Keywords: stars: fundamental parameters - stars: horizontal branch -
stars: variables: RR Lyrae - globular clusters: general
Abstract:
We have performed a critical evaluation of the membership status of
all variable stars in globular clusters recorded in the Catalogue of
Variable Stars in Globular Clusters (CVSGC) curated by Christine
Clement. To this end, we employed the systematic and bulky membership
analysis performed by E. Vasiliev and H. Baumgardt based on the proper
motions and parallaxes given in Gaia-EDR3. We found numerous variables
in the CVSGC which are in fact field stars, which is particularly the
case for globular clusters located in the Galactic bulge. Using the
newly acquired list of reliable cluster members we examine the
Oosterhoff dichotomy present among the Milky Way (MW) globular
clusters using their RR Lyrae stars content. We confirm the presence
of the Oosterhoff gap, separating both Oosterhoff groups. The
Oosterhoff gap is mostly populated by globular clusters associated
with MW dwarf galaxies and globular clusters with a low number of
fundamental mode RR Lyrae variables. Several of the clusters in the
Oosterhoff gap were previously linked to past merger events (e.g.
Kraken/Heracles).
Description:
In this work, we propose to assign a membership likely status to each
one of the variables presently catalogued in the CVSGC (Clement et
al., Cat. V/150), using the Gaia-EDR3 proper motions and the
systematic membership analysis performed for 170 GCs by Vasiliev &
Baumgardt (2021MNRAS.505.5978V 2021MNRAS.505.5978V, Cat. J/MNRAS/505/5978).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 58 119 Studied clusters
members.dat 78 6034 Variable stars and their cluster membership
probabilities (table 2)
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See also:
V/150 : Updated catalog of variable stars in globular clusters
(Clement+ 2017)
J/MNRAS/505/5978 : Gaia EDR3 view on Galactic globular clusters
(Vasiliev+, 2021)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name
11- 12 I2 h RAh Simbad right ascension (J2000)
14- 15 I2 min RAm Simbad right ascension (J2000)
17- 21 F5.2 s RAs Simbad right ascension (J2000)
23 A1 --- DE- Simbad declination sign (J2000)
24- 25 I2 deg DEd Simbad declination (J2000)
27- 28 I2 arcmin DEm Simbad declination (J2000)
30- 33 F4.1 arcsec DEs Simbad declination (J2000)
36- 38 I3 --- N Number of stars in members.dat table
40- 58 A19 --- SName Simbad name of the cluster
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Byte-by-byte Description of file: members.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluter name
10- 19 A10 --- VName Variable name
21- 22 A2 --- Cooframe Coordinate reference frame (1)
24- 35 F12.8 deg RAdeg ? Right Ascension (J2000) except if
Cooframe = XA for NGC 1851 stars
37- 48 F12.8 deg DEdeg ? Declination (J2000) except if
Cooframe = XA for NGC 1851 stars
50- 55 A6 --- Vartype Variability type
57- 63 F7.4 d Period ?=- Variability periods
66- 75 F10.5 --- Memprob ?=-999 Membership probability
77- 78 A2 --- Probname Code for membership probability (2)
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Note (1): Coordinate reference frame as follows:
R0 denotes RA, DEC in the J2000 coordinates
XA denotes X, Y in arcseconds (for 6 stars in NGC 1851)
Note (2): Code for membership probabilities as follows:
m1 = Pmemb ≥ 0.85
m2 = 0.7 ≤ Pmemb < 0.85
m3 = 0.5 ≤ Pmemb < 0.7
f = Pmemb ≤ 0.5
u = unknown
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Acknowledgements:
Armando Arellano Ferro, armando(at)astro.unam.mx
(End) Patricia Vannier [CDS] 05-Nov-2024