J/A+A/678/A158 APOGEE red-giant stars spectroscopic age estimates (Anders+ 2023)
Spectroscopic age estimates for APOGEE red-giant stars:
Precise spatial and kinematic trends with age in the Galactic disc.
Anders F., Gispert P., Ratcliffe B., Chiappini C., Minchev I., Nepal S.,
Queiroz A.B.A., Amarante J.A.S., Antoja T., Casali G., Casamiquela L.,
Khalatyan A., Miglio A., Perottoni H., Schultheis M.
<Astron. Astrophys. 678, A158 (2023)>
=2023A&A...678A.158A 2023A&A...678A.158A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, ages ; Infrared sources
Keywords: Galaxy: evolution - Galaxy: stellar content - methods: data analysis -
methods: statistical - stars: abundances - stars: late-type
Abstract:
We tabulate spectroscopic stellar age estimates for 178825 red-giant
stars observed by the APOGEE survey (Majewski et al.,
2017AJ....154...94M 2017AJ....154...94M, Cat. III/284) with a median statistical
uncertainty of 17%. The ages were obtained with the supervised
machine-learning technique XGBoost (Chen & Guestrin, 2016,
arXiv:1603.02754), trained on a high-quality dataset of 3060 red-giant
and red-clump stars with asteroseismic ages observed by both APOGEE
and Kepler (Miglio et al., 2021A&A...645A..85M 2021A&A...645A..85M, Cat. J/A+A/645/A85).
Two sets of age estimates are delivered in this table: The first five
columns contain the results of the fiducial XGBoost model (obtained
with version 1.7.6 of the xgboost python package) mostly used in the
accompanying paper. The final five columns use a XGBoost quantile
regression (using version 2.0.0 of the xgboost python package). Our
age estimates constitute a useful database for studying the evolution
of the Galactic disc.
Description:
We successfully use the XGBoost algorithm to accurately estimate
spectroscopic ages for 178825 APOGEE DR17 red-giant stars located
close to the red clump (2.2<logg<3.4, 4400K<Teff<5200K) with a median
statistical uncertainty of 17%.
The source code used to create the catalogue is publicly available at
https://github.com/fjaellet/xgboost_chem_ages.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 165 178825 APOGEE spectroscopic age catalogue (table A1)
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See also:
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
J/A+A/645/A85 : Age dissection of the Milky Way discs (Miglio+, 2021)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- APOGEE APOGEE_ID (APOGEE_ID) (1)
21- 25 F5.2 Gyr spAge Spectroscopic age from fiducial XGBoost model
(specagexgb)
27- 31 F5.2 Gyr spAgeCal Calibrated spectroscopic age
(see paper Fig. 4) (specagexgb_calib)
33- 36 F4.2 Gyr e_spAge Fiducial age uncertainty (see paper Fig. 4)
(specagexgb_uncert)
38- 88 A51 --- f_spAge Warning flag for potentially problematic
stars (specagexgb_flag) (2)
90- 94 F5.2 Gyr spAgeqr Spectroscopic age from XGBoost quantile
regression (specagexgb_quantilereg)
96-100 F5.2 Gyr spAgeqrCal Calibrated quantile regression age
(specagexgbquantileregcalib)
102-106 F5.2 Gyr e_spAgeqrCal [] Quantile regression age lower 1sigma
uncertainty (specagexgbquantileregsigl)
108-112 F5.2 Gyr E_spAgeqrCal [] Quantile regression age upper 1sigma
uncertainty (specagexgbquantileregsigu)
114-165 A52 --- f_spAgeqrCal Warning flag for potentially problematic
stars (specagexgbquantileregflag) (2)
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Note (1): For duplicate APOGEE_IDs, the APOGEE DR17 (Abdurro'uf et al.,
2022ApJS..259...35A 2022ApJS..259...35A) entry with the highest signal-to-noise estimate (SNREV)
is reported in the catalogue.
Note (2): The warning flag columns can take the values
BLUERTHANTRAINING_SET, REDDERTHANTRAINING_SET, HIGH_VSINI,
APPARENTLYYOUNGALPHA_RICH, and combinations thereof.
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Acknowledgements:
Friedrich Anders, fanders(at)icc.ub.edu
(End) Patricia Vannier [CDS] 28-Aug-2023