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J/A+A/612/A99    Gaia-ESO Survey in 7 open star cluster fields  (Randich+, 2018)

The Gaia-ESO Survey: open clusters in Gaia-DR1. A way forward to stellar age calibration. Randich S., Tognelli E., Jackson R., Jeffries R.D., Degl'Innocenti S., Pancino E., Re Fiorentin P., Spagna A., Sacco G., Bragaglia A., Magrini L., Prada Moroni P.G., Alfaro E., Franciosini E., Morbidelli L., Roccatagliata V., Bouy H., Bravi L., Jimenez-Esteban F.M., Jordi C., Zari E., Tautvaisiene G., Drazdauskas A., Mikolaitis S., Gilmore G., Feltzing S., Vallenari A., Bensby T., Koposov S., Korn A., Lanzafame A., Smiljanic R., Bayo A., Carraro G., Costado M.T., Heiter U., Hourihane A., Jofre P., Lewis J., Monaco L., Prisinzano L., Sbordone L., Sousa S.G., Worley C.C., Zaggia S. (Gaia-ESO collaboration) <Astron. Astrophys. 612, A99 (2018)> =2018A&A...612A..99R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Abundances, [Fe/H] ; Effective temperatures ; Equivalent widths ; Radial velocities ; Rotational velocities ; Spectroscopy Keywords: parallaxes - surveys - stars: evolution - open clusters and associations: general - Abstract: Determination and calibration of the ages of stars, which heavily rely on stellar evolutionary models, are very challenging, while representing a crucial aspect in many astrophysical areas. We describe the methodologies that, taking advantage of Gaia-DR1 and the Gaia-ESO Survey data, enable the comparison of observed open star cluster sequences with stellar evolutionary models. The final, long-term goal is the exploitation of open clusters as age calibrators. We perform a homogeneous analysis of eight open clusters using the Gaia-DR1 TGAS catalogue for bright members and information from the Gaia-ESO Survey for fainter stars. Cluster membership probabilities for the Gaia-ESO Survey targets are derived based on several spectroscopic tracers. The Gaia-ESO Survey also provides the cluster chemical composition. We obtain cluster parallaxes using two methods. The first one relies on the astrometric selection of a sample of bona fide members, while the other one fits the parallax distribution of a larger sample of TGAS sources. Ages and reddening values are recovered through a Bayesian analysis using the 2MASS magnitudes and three sets of standard models. Lithium depletion boundary (LDB) ages are also determined using literature observations and the same models employed for the Bayesian analysis. For all but one cluster, parallaxes derived by us agree with those presented in Gaia Collaboration (2017A&A...601A..19G, Cat. J/A+A/601/A19), while a discrepancy is found for NGC 2516; we provide evidence supporting our own determination. Inferred cluster ages are robust against models and are generally consistent with literature values. The systematic parallax errors inherent in the Gaia DR1 data presently limit the precision of our results. Nevertheless, we have been able to place these eight clusters onto the same age scale for the first time, with good agreement between isochronal and LDB ages where there is overlap. Our approach appears promising and demonstrates the potential of combining Gaia and ground-based spectroscopic datasets. Description: We present spectroscopic parameters of the targets observed by the Gaia-ESO Survey in seven open star cluster fields. The spectra have been obtained with FLAMES on the VLT and the UVES or Giraffe spectrographs. The parameters have been derived by the Gaia-ESO consortium during the fourth analysis cycle (iDR4). The tables list, for each cluster, the parameters used for the membership analysis. Specifically, we include: the star ID; cluster name; instrument (UVES or Giraffe); stellar parameters (effective temperature, surface gravity, metallicity) and their errors; equivalent width of the Li 6707.8Å line and error; a flag indicating if the Li EW is a detection (flag=0) or an upper limit (flag=1); gamma index and error; radial and rotational velocities and errors; upper limits in rotational velocities; membership probabilities. For all clusters but NGC 2451, Memb(PA) should be considered. For NGC 2451 Memb(PA) and Memb(PB) should be considered for clusters A and B, respectively. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file ic2391.dat 158 447 Parameters for IC2391 ic2602.dat 158 1505 Parameters for IC2602 ic4665.dat 158 579 Parameters for IC4665 ngc2451.dat 158 1696 Parameters for NGC2451 ngc2516.dat 158 796 Parameters for NGC2516 ngc2547.dat 158 510 Parameters for NGC2547 ngc6633.dat 158 564 Parameters for NGC6633
See also: I/337 : Gaia DR1 (Gaia Collaboration, 2016) Byte-by-byte Description of file: ic*.dat ngc*.dat
Bytes Format Units Label Explanations
1- 16 A16 --- CName Star ID (HHMMSSss+DDMMSSs) 18- 24 A7 --- Cluster Cluster name 26- 32 A7 --- Inst Intrument XX 34- 38 I5 K Teff Effective temperature 40- 43 I4 K e_Teff ?=-999 Effective temperature error 45- 52 F8.3 [cm/s2] logg ?=-999 10-logarithm surface gravity 54- 61 F8.3 [cm/s2] e_logg ?=-999 10-logarithm surface gravity error 63- 70 F8.3 [-] [Fe/H] ?=-999 Metallicity 72- 79 F8.3 [-] e_[Fe/H] ?=-999 Metallicity error 81 A1 --- l_EWLi [<] Upper limit flag on EWLi 82- 89 F8.3 [0.1pm] EWLi ?=-999 Lithium line equivalent width 91- 98 F8.3 [0.1pm] e_EWLi ?=-999 Lithium line equivalent width error 100-103 I4 --- f_EWLi [0/3]?=-999 Flag for lithium line equivalent width (1) 105-112 F8.3 --- Gamma ?=-999 Gamma index 114-121 F8.3 --- e_Gamma ?=-999 Gamma index error 123-130 F8.3 km/s RV ?=-999 Radial velocity 132-139 F8.3 km/s e_RV ?=-999 Radial velocity error 141-146 F6.3 --- MembPA ?=-1 Membership probability: population A 148-153 F6.3 --- MembPB ?=-1 Membership probability: population B 155-158 I4 --- ID Sequential ID number
Note (1): Upper limit flag as follows: 0 = not an upper limit 3 = upper limit -999 = data not available
Acknowledgements: Sofia Randich, randich(at)arcetri.astro.it
(End) Patricia Vannier [CDS] 23-Nov-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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