J/MNRAS/505/1607 Tidal tails in the open cluster NGC 752 (Bhattacharya+, 2021)
Tidal tails in the disintegrating open cluster NGC 752.
Bhattacharya S., Agarwal M., Rao K.K., Vaidya K.
<Mon. Not. R. Astron. Soc., 505, 1607-1613 (2021)>
=2021MNRAS.505.1607B 2021MNRAS.505.1607B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Milky Way ; Parallaxes, trigonometric ;
Photometry, G band ; Optical ; Infrared ; Ultraviolet ;
Proper motions ; Radial velocities
Keywords: methods: data analysis -
open clusters and associations: individual: NGC 752
Abstract:
We utilize the robust membership determination algorithm, ML-MOC, on
the precise astrometric and deep photometric data from Gaia Early Data
Release 3 within a region of radius 5 degrees around the centre of the
intermediate-age Galactic open cluster NGC 752 to identify its member
stars. We report the discovery of the tidal tails of NGC 752,
extending out to ∼35 pc on either side of its denser central region
and following the cluster orbit. From comparison with PARSEC stellar
isochrones, we obtain the mass function of the cluster with a slope,
Χ = -1.26 ± 0.07. The high negative value of Χ is indicative
of a disintegrating cluster undergoing mass segregation. Χ is more
negative in the intra-tidal regions as compared to the outskirts of
NGC 752. We estimate a present day mass of the cluster,
MC = 297 ± 10 M☉. Through mass-loss due to stellar evolution
and tidal interactions, we further estimate that NGC 752 has lost nearly
95.2-98.5 per cent of its initial mass, Mi = 0.64-2 * 104M☉.
Description:
Agarwal et al. (2021MNRAS.502.2582A 2021MNRAS.502.2582A) using Gaia DR2
(2018A&A...616A...1G 2018A&A...616A...1G, Cat. I/345) data with their novel machine
learning membership determination algorithm found hints of tidal tails
in NGC 752. Also, Hu et al. (2021ApJ...912....5H 2021ApJ...912....5H, Cat. J/ApJ/912/5)
also identify the elongated morphology of the peripheral regions of
NGC 752 from the Gaia DR2 data using the members identified by
Cantat-Gaudin et al. (2018A&A...618A..93C 2018A&A...618A..93C, Cat. J/A+A/618/A93).
As the first step, we do a membership selection in NGC 752 from the
Gaia EDR3 (2021A&A...649A...1G 2021A&A...649A...1G, Cat. I/350) data set is carried out in
a region of radius 5 degrees around its centre. This sample is termed
All sources. We use ML-MOC (Agarwal et al. 2021MNRAS.502.2582A 2021MNRAS.502.2582A) to
identify cluster members using the proper motion and parallax
information. It identifies cluster members in the PM-ω parameter
space, independent of the spatial density of the cluster, thereby
allowing for the identification of faint extended spatial structures
such as tidal tails.Their spatial, PM, and ω distributions are
shown as Sample sample (see Section 2 Fig. 1).
For the second step, a three-dimensional Gaussian mixture model (GMM;
Mclachlan & Peel 2000, Wiley Series in Probability and Statistics,
2000, Finite Mixture Models, Vol. 44, Wiley, New York) is used in the
PM-ω parameter space of the Sample sources sample to distinguish
between the cluster and field members, also assigning a membership
probability (pmemb). Those sources having pmemb ≥ 0.6 are considered
as high probability members, also including all the radial velocity
members. A small number of stars having 0.2 ≤ pmemb ≤ 0.6 are also
considered as members if their values lie within the range of values
specified by the members that have pmemb ≥ 0.8.
This results in the identification of 282 members in NGC 752 whose
spatial, PM, and ω distributions are also shown (see Section 2
Fig. 1). The identified members with their IDs, astrometry,
photometry, radial velocity, and pmemb have been tabulated in
table1.dat.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 282 *Gaia EDR3 members identified in NGC 752
using ML-MOC
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Note on table1.dat: ML-MOC means Machine Learning based Membership
determination for Open Clusters. Except pmemb values computed in this work,
all data come from Gaia EDR3 (2021A&A...649A...1G 2021A&A...649A...1G, Cat. I/350).
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
J/ApJ/912/5 : Parameters of 265 open clusters (Hu+, 2021)
J/A+A/618/A93 : Gaia DR2 open clusters in the Milky Way (Cantat-Gaudin+, 2018)
J/ApJ/862/33 : Improved & expanded membership catalog for NGC752
(Agueros+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 I18 --- GaiaEDR3 Gaia EDR3 source identifier (GaiaID)
20- 37 F18.15 deg RAdeg Barycentric right ascension of the source
(ICRS) at Ep=2016.0 (RA)
39- 56 F18.15 deg DEdeg Barycentric declination of the source
(ICRS) at Ep=2016.0 (Dec)
58- 62 F5.3 mas plx Absolute stellar parallax of the source
at the Ep=2016.0 (omega)
64- 69 F6.3 mas/yr pmRA Proper motion in right ascension pmRA*cosDE
of the source in ICRS at Ep=2016.0 (mualpha)
71- 77 F7.3 mas/yr pmDE Proper motion in declination direction
(mudelta)
79- 83 F5.2 mag Gmag G-band mean magnitude (Vega) (G)
85- 89 F5.2 mag BPmag Integrated BP mean magnitude (Vega) (BP)
91- 95 F5.2 mag RPmag Integrated RP mean magnitude (Vega) (RP)
97-102 F6.2 km/s RV ? Radial velocity from Gaia EDR3 copied
from Gaia DR2 (RV)
104-107 F4.2 --- pmemb Computed NGC 752 membership probability
(pmemb)
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 28-May-2024