J/A+A/640/A127 Open cluster properties with Gaia and LAMOST (Zhong+, 2020)
Exploring open cluster properties with Gaia and LAMOST.
Zhong J., Chen L., Wu D., Li L., Bai L., Hou J.
<Astron. Astrophys. 640, A127 (2020)>
=2020A&A...640A.127Z 2020A&A...640A.127Z (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Positional data
Keywords: open clusters and associations: general -
galaxies: kinematics and dynamics - methods: data analysis - catalogs
Abstract:
In Gaia DR2, an unprecedented high level of precision has been reached
at sub-milliarcsecond for astrometry and millimagnitudes for
photometry. Using cluster members identified with the astrometry and
photometry in Gaia DR2, we can obtain a reliable determination of
cluster properties. However, because of the shortcomings of Gaia
spectroscopic observations in dealing with densely crowded cluster
regions, the RVs and metallicity values for cluster member stars from
Gaia DR2 are still lacking. It is necessary to combine the Gaia data
with the data from large spectroscopic surveys, such as LAMOST,
APOGEE, GALAH, and Gaia-ESO.
In this study, we aim to improve the cluster properties by combining
the LAMOST spectra. In particular, we provide the list of cluster
members with spectroscopic parameters as an add-value catalog in
LAMOST DR5, which can be used to perform detailed study for a better
understanding on the stellar properties, by using their spectra and
fundamental properties from the host cluster.
We cross-matched the spectroscopic catalog in LAMOST DR5 (Luo et al.,
2019, Cat. V/164) with the identified cluster members in Cantat-Gaudin
et al. (2018, Cat. J/A+A/615/A49). We then used members with
spectroscopic parameters to derive statistical properties of open
clusters.We obtained a list of 8811 members with spectroscopic
parameters and a catalog of 295 cluster properties. In addition, we
study the radial and vertical metallicity gradient and age-metallicity
relation with the compiled open clusters as tracers, finding slopes of
-0.053±0.004dex/kpc, -0.252±0.039dex/kpc and 0.022±0.008dex/Gyr,
respectively. Both slopes of metallicity distribution relation for
young clusters (0.1Gyr<Age<2Gyr) and the age-metallicity
relation for clusters within 6Gyr are consistent with literature
results. In order to fully study the chemical evolution history in the
disk, more spectroscopic observations for old and distant open
clusters are needed for further investigation.
Description:
We used the cluster members identified by Cantat-Gaudin et sl. (2018,
Cat. J/A+A/615/A49) to cross-match with the LAMOST spectroscopic
catalog (Luo et al., 2019, Cat. V/164). A total of 8811 member stars
with spectrum data were provided. Using the spectral information of
cluster members, we also provided average RVs of 295 OCs and
metallicity of 220 OCs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ocs.dat 439 295 Open cluster sample
memb.dat 383 8811 Members
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/A+A/615/A49 : TGAS stars membership in 128 open clusters
(Cantat-Gaudin+, 2018)
Byte-by-byte Description of file: ocs.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Cluster Cluster name
19- 25 F7.3 deg RAdeg [] Mean right ascension (ICRS) at Ep=2015.0
of members in CG18 (J2000)
27- 32 F6.3 deg DEdeg Mean declination (ICRS) at Ep=2015.0
of members in CG18 (J2000)
34- 40 F7.3 mas/yr pmRA* Mean proper motion along RA, pmRA*cosDE,
of members in CG18
42- 46 F5.3 mas/yr e_pmRA* Standard deviation of pmRA* of members
in CG18
48- 54 F7.3 mas/yr pmDE Mean proper motion along DE of members
in CG18
56- 60 F5.3 mas/yr e_pmDE Standard deviation of pmDE of members
in CG18
62- 68 F7.1 pc DMode Most likely distance of clusters in CG18
70- 83 F14.9 km/s RV Mean radial velocity measured from member
spectra in LAMOST
85- 95 F11.7 km/s e_RV ? Standard deviation of RV
97- 99 I3 --- o_RV Number of stars used for RV estimation
101 A1 --- f_RV [Y] Flag of Gaussian fitting process for
RV estimation
105-117 F13.10 [-] [Fe/H] Mean [Fe/H] measured from member spectra
in LAMOST
119-130 E12.9 [-] e_[Fe/H] ? Standard deviation of FeH
132-134 I3 --- o_[Fe/H] Number of stars used for FeH estimation
136 A1 --- f_[Fe/H] [Y] Flag of Gaussian fitting process for
[Fe/H] estimation
140-150 F11.4 pc GX ? Galactocentric coordinate points to
the direction opposite to that of the Sun
152-164 F13.7 pc e_GX ? Mean errors of GX coordinate calculation
166-178 F13.7 pc GY ? Galactocentric coordinate points to
the direction of Galactic rotation
180-192 F13.8 pc e_GY ? Mean errors of GY coordinate calculation
194-206 F13.8 pc GZ ? Galactocentric coordinate points toward
the North Galactic Pole
208-220 F13.9 pc e_GZ ? Mean errors of GZ coordinate calculation
222-234 F13.8 km/s U Galactocentric space velocity in X axis
236-247 F12.8 km/s e_U ? Mean errors of U velocity calculation
249-258 F10.6 km/s V Galactocentric space velocity in Y axis
260-271 F12.8 km/s e_V ? Mean errors of V velocity calculation
273-284 F12.8 km/s W Galactocentric space velocity in Z axis
286-296 F11.8 km/s e_W ? Mean errors of W velocity calculation
298-317 F20.16 pc Rap Averaged apogalactic distances from
the Galactic centre
319-337 F19.16 pc Rperi Averaged perigalactic distances from
the Galactic centre
339-358 F20.18 --- EC Eccentricity calculated
as e=(Rap-Rperi)/(Rap+Rperi)
360-379 F20.18 pc Zmax Averaged maximum vertical distances above
the Galactic plane
381-390 F10.4 pc RGC ? Galactocentric distance assuming
the Sun is located at 8340 pc
392-405 F14.8 pc e_RGC ? Mean errors of Galactocentric
distance calculation
407-412 F6.3 Gyr Ageref Age from literature results determined by
the isochrone fit
414-423 F10.5 pc Distref Distance from literature results determined
by the isochrone fit
425-435 F11.9 mag E(B-V)ref Reddening from literature results
determined by the isochrone fit
437-439 A3 --- Ref Label of referred literature for age,
distance and E(B-V) determination (1)
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Note (1): References as follows:
(1) = Bossini et al. (2019, Cat. J/A+A/623/A108)
(2) = Kharchenko et al. (2013, Cat. J/A+A/558/A53)
(3) = Dias et al. (2002, Cat. J/A+A/388/168)
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Byte-by-byte Description of file: memb.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- obsid Object unique spectra ID in LAMOST DR5
11- 29 A19 --- LAMOST Object designation in LAMOST DR5
31- 41 F11.7 deg RAdeg Object right ascension in LAMOST DR5 (J2000)
43- 52 E10.7 deg DEdeg Object declination in LAMOST DR5 (J2000)
54- 59 F6.2 --- snrg Signal-to-noise ration of g filter
in LAMOST spectrum
61- 66 F6.2 --- snrr Signal-to-noise ration of r filter
in LAMOST spectrum
68- 73 F6.2 --- snri Signal-to-noise ration of i filter
in LAMOST spectrum
75- 96 E22.19 km/s RV2d ?=- Radial velocity derived by the
LAMOST 2D pipeline
98-117 E20.17 km/s e_RV2d ?=- Uncertainty of radial velocity derived
by the LAMOST 2D pipeline
119-125 F7.2 km/s RV1d ?=- Radial velocity derived by the
LAMOST 1D pipeline
127-135 F9.2 km/s e_RV1d ?=- Uncertainty of radial velocity derived
by the LAMOST 1D pipeline
137-143 F7.2 K Teff ? Effective temperature derived by the
software of ULYSS
145-153 F9.2 K e_Teff ?=- Error of effective temperature derived
by the software of ULYSS
155-159 F5.3 [cm/s2] logg ? Surface gravity derived by the software of
ULYSS
161-169 F9.3 [cm/s2] e_logg ?=- Error of surface gravity derived by
the software of ULYSS
171-176 F6.3 [-] [Fe/H] ? Metallicity [Fe/H] derived by the the
software of ULYSS
178-186 F9.3 [-] e_[Fe/H] ?=- Error of [Fe/H] derived by the software
of ULYSS
188-206 I19 --- GaiaDR2 Gaia DR2 source id
208-229 E22.18 mas plx Parallax in Gaia DR2
231-250 F20.18 mas e_plx Parallax error in Gaia DR2
252-273 E22.18 mas/yr pmRA* Proper motion along RA, pmRA*cosDE,
in Gaia DR2
275-294 F20.18 mas/yr e_pmRA* Error of pmRA in Gaia DR2
296-317 E22.18 mas/yr pmDE Proper motion along DE in Gaia DR2
319-338 F20.18 mas/yr e_pmDE Error of pmDE in Gaia DR2
340-349 F10.7 mag Gmag G-band magnitude in Gaia DR2
351-361 E11.5 mag BP-RP ? BP minus RP color in Gaia DR2
363-365 F3.1 --- proba Membership probability provided by CG18
367-383 A17 --- Cluster Corresponding cluster name
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Acknowledgements:
Jing Zhong, jzhong(at)shao.ac.cn
(End) Patricia Vannier [CDS] 15-Jun-2020