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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 742671.0, MPI für Astronomie / Publikationen_mpia
Label transfer from APOGEE to LAMOST: Precise stellar parameters for 450,000 LAMOST giants
Authors:Ho, A. Y. Q.; Ness, M. K.; Hogg, D. W.; Rix, H.-W.; Liu, C.; Yang, F.; Zhang, Y.; Hou, Y.; Wang, Y.
Date of Publication (YYYY-MM-DD):2017
Title of Journal:The Astrophysical Journal
Issue / Number:1
Start Page:id. 5 (15 pp)
Audience:Not Specified
Abstract / Description:In this era of large-scale spectroscopic stellar surveys, measurements of stellar attributes (“labels,” i.e., parameters and abundances) must be made precise and consistent across surveys. Here, we demonstrate that this can be achieved by a data-driven approach to spectral modeling. With The Cannon, we transfer information from the APOGEE survey to determine precise {T}{eff}, {log} {\text{}}g, [{Fe}/{{H}}], and [α /{{M}}] from the spectra of 450,000 LAMOST giants. The Cannon fits a predictive model for LAMOST spectra using 9952 stars observed in common between the two surveys, taking five labels from APOGEE DR12 as ground truth {T}{eff}, {log} {\text{}}g, [{Fe}/{{H}}], [α /{{M}}], and K-band extinction {A}{{k}}. The model is then used to infer {T}{eff}, {log} {\text{}}g, [{Fe}/{{H}}], and [α /{{M}}] for 454,180 giants, 20% of the LAMOST DR2 stellar sample. These are the first [α /{{M}}] values for the full set of LAMOST giants, and the largest catalog of [α /{{M}}] for giant stars to date. Furthermore, these labels are by construction on the APOGEE label scale; for spectra with S/N > 50, cross-validation of the model yields typical uncertainties of 70 K in {T}{eff}, 0.1 in {log} {\text{}}g, 0.1 in [{Fe}/{{H}}], and 0.04 in [α /{{M}}], values comparable to the broadly stated, conservative APOGEE DR12 uncertainties. Thus, by using “label transfer” to tie low-resolution (LAMOST R ≈ 1800) spectra to the label scale of a much higher-resolution (APOGEE R ≈ 22,500) survey, we substantially reduce the inconsistencies between labels measured by the individual survey pipelines. This demonstrates that label transfer with The Cannon can successfully bring different surveys onto the same physical scale.
Free Keywords:catalogs; methods: data analysis; methods: statistical; stars: abundances; stars: fundamental parameters; techniques: spectroscopic
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0004-637X %R 10.3847/1538-4357/836/1/5
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