J/AJ/150/187 Abundances and stellar parameters of LAMOST stars (Lee+, 2015)
Application of the SEGUE stellar parameter pipeline to LAMOST stellar spectra.
Lee Y.S., Beers T.C., Carlin J.L., Newberg H.J., Hou Y., Li G., Luo A.-L.,
Wu Y., Yang M., Zhang H., Zhang W., Zhang Y.
<Astron. J., 150, 187 (2015)>
=2015AJ....150..187L 2015AJ....150..187L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, atmospheres ; Abundances ; Abundances, [Fe/H] ;
Effective temperatures
Keywords: methods: data analysis - stars: abundances -
techniques: imaging spectroscopy
Abstract:
We describe an application of the SEGUE Stellar Parameter Pipeline
(SSPP) to medium-resolution stellar spectra obtained by the Large Sky
Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), in order to
determine estimates of the stellar atmospheric parameters (Teff,
logg, and [Fe/H]) and the abundance ratios ([α/Fe] and [C/Fe]).
By performing a coordinate match with the LAMOST stellar database, we
selected stars with LAMOST spectra in common with stars having
available spectroscopy from the Apache Point Observatory Galactic
Evolution Experiment (APOGEE), the RAdial Velocity Experiment (RAVE),
and the Sloan Extension for Galactic Understanding and Exploration
(SEGUE). We ran the selected LAMOST stellar spectra from each survey
through SSPP, and compared the stellar parameters down to
signal-to-noise ratio (S/N) of 10 and chemical abundances down to
S/N=20 derived by SSPP with those determined by the APOGEE, RAVE, and
SEGUE software pipelines. Our results show that the derived stellar
parameters generally agree quite well, even though there exist some
small systematic offsets with small scatter in Teff, logg, and
[Fe/H], due to the use of different temperature scales, abundance
scales, and calibrations adopted by each survey. Comparison of the
[α/Fe] determinations for LAMOST spectra suggests no sign of
significant systematic offsets (< -0.04dex), with a small scatter
(<0.08dex) relative to stars in common with APOGEE and SEGUE. The
[C/Fe] estimates determined for the LAMOST spectra also exhibit good
agreement, with a very small offset (∼0.01dex) and scatter (∼0.12dex)
relative to the SEGUE stars, while there exists about a -0.19dex
offset, with a small scatter of ∼0.13dex, for the APOGEE sample. Due
to the existence of small offsets in the stellar parameters and
abundances among difference data sets, optimal results when combining
the different data sets will be obtained by removing the offsets. Once
accomplished, the stellar parameters and chemical abundances estimated
by SSPP from the LAMOST stellar spectra should provide a reliable
database for studies of the Galactic disk and halo systems.
Description:
By performing a coordinate match with the Large Sky Area Multi-Object
Fiber Spectroscopic Telescope (LAMOST; see DR1 in Luo et al. 2015,
cat. V/146) stellar database, we selected stars with LAMOST spectra in
common with stars having available spectroscopy from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE; Majewski et al.
2015, submitted), the RAdial Velocity Experiment (RAVE; see Kordopatis
et al. 2013, cat. III/272), and the Sloan Extension for Galactic
Understanding and Exploration (SEGUE; see Yanny et al. 2009, cat.
J/AJ/137/4377).
The LAMOST Experiment for Galactic Understanding and Exploration
(LEGUE) survey is an ongoing spectroscopic survey being conducted with
the Guoshoujing telescope in northeast China. This telescope employs a
fixed 4-m Schmidt-type reflector with 4000 optical fibers in the focal
plane to obtain spectra of astronomical objects in a 5° field of
view. The LEGUE and SEGUE surveys have very similar spectral coverage
and resolving power (R∼1800). The LAMOST stellar targets mostly
comprise stars brighter than r< 17, whereas the SEGUE stars range from
r=14 to r=21. SEGUE-1 was executed during the second phase of the
Sloan Digital Sky Survey (SDSS-II). This effort was continued as
SEGUE-2 during the third phase of SDSS (SDSS-III).
APOGEE was designed to obtain high-resolution near-infrared spectra
(in the H-band between 1.51 and 1.70µm). The spectra obtained by
APOGEE have a resolving power R∼22500 and high S/N (>100). APOGEE-1
was a sub-survey of SDSS-III, and is now completed. Its extension,
APOGEE-2, is presently underway as part of SDSS-IV.
The RAVE survey was designed to observe about a million stars in the
southern hemisphere, and obtain optical spectra over the wavelength
range 8410-8795Å, the region of the CaII triplet, at a resolving
power R∼7500.
SEGUE-1 and SEGUE-2 have employed the SEGUE Stellar Parameter Pipeline
(SSPP; Lee et al. 2008, cat. J/AJ/136/2050; Allende Prieto et al.
2008, cat. J/AJ/136/2070; Smolinski et al. 2011, cat. J/AJ/141/89; Lee
et al. 2011, cat. J/AJ/141/90) to derive the stellar atmospheric
parameters and available elemental abundance ratios. We modified and
upgraded SSPP so that it can process the LAMOST stellar spectra and
derive the fundamental stellar parameters as well as the
α-element abundances ([α/Fe]) and carbon-to-iron ratios
([C/Fe]) for these stars. The derived atmospheric parameters and
chemical abundances obtained by SSPP for LAMOST stars are then
compared with those from the stars also observed by SEGUE, APOGEE, and
RAVE.
Table1 lists the LAMOST stars with appropriate stellar parameters from
APOGEE, RAVE, and SEGUE. It also lists the LAMOST/SEGUE Stellar
Parameter Pipeline (LSSPP) parameters and abundances. We do not report
[α/Fe] and [C/Fe] for stars with S/N<20 and the range outside of
Teff=4400-6700K in the table.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 7908 List of LAMOST stars used to validate LAMOST/SEGUE
Stellar Parameter Pipeline (LSSPP) parameters
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See also:
V/146 : LAMOST DR1 catalogs (Luo+, 2015)
III/272 : RAVE 4th data release (Kordopatis+, 2013)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
J/MNRAS/448/822 : LAMOST candidate members of star clusters (Xiang+, 2015)
J/AJ/146/133 : SDSS-III APOGEE DR10 stellar parameters (Meszaros+, 2013)
J/AJ/142/193 : RAVE stellar elemental abundances (DR1) (Boeche+, 2011)
J/AJ/141/90 : SEGUE stellar parameter pipeline. V. (Lee+, 2011)
J/AJ/141/89 : SEGUE stellar parameter pipeline. IV. (Smolinski+, 2011)
J/other/RAA/11.924 : Atmospheric parameters for 771 stars (Wu+, 2011)
J/ApJ/737/9 : RAVE spectroscopy of stars in thick disk (Ruchti+, 2011)
J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)
J/AJ/136/2070 : SSPP. III. (Allende Prieto+, 2008)
J/AJ/136/2050 : SEGUE stellar parameter pipeline (SSPP). II. (Lee+, 2008)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- --- [LAMOST ]
8- 26 A19 --- LAMOST LAMOST identifier (JHHMMSS.ss+DDMMSS.s)
28- 31 I4 K RTeff Reference effective temperature (1)
33- 37 F5.3 [cm/s2] Rlogg Log reference surface gravity (1)
39- 45 F7.3 [Sun] R[Fe/H] Log reference Fe/H abundance ratio (1)
47- 53 F7.3 [Sun] R[a/Fe] ? Log reference α/Fe abundance ratio (1)
55- 61 F7.3 [Sun] R[C/Fe] ? Log reference C/Fe abundance ratio (1)
63- 68 F6.1 --- RS/N Reference Signal-to-Noise (1)
70- 73 I4 K LTeff LSSPP effective temperature (2)
75- 79 F5.3 [cm/s2] Llogg Log LSSPP surface gravity (2)
81- 87 F7.3 [Sun] L[Fe/H] Log LSSPP Fe/H abundance ratio (2)
89- 95 F7.3 [Sun] L[a/Fe] ? Log LSSPP α/Fe abundance ratio (2)
97-103 F7.3 [Sun] L[C/Fe] ? Log LSSPP C/Fe abundance ratio (2)
105-109 F5.1 --- LS/N LSSPP Signal-to-Noise (2)
111-116 A6 --- Survey Survey identifier (APOGEE, RAVE, or SEGUE) (3)
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Note (1): The reference parameters come from each individual survey given in the
Survey column.
Note (2): The LAMOST/SEGUE Stellar Parameter Pipeline (LSSPP) parameters are the
ones delivered by SSPP on LAMOST spectra. This table only includes the
LAMOST stars that were released to the public, LAMOST DR1 (Luo et al. 2015,
cat. V/146). LAMOST DR2 data are only available to internal collaborators.
For this reason, the total number of entries in this table is not the same
as shown in the figures of the paper.
Note (3): Survey name defined as below:
APOGEE = Apache Point Observatory Galactic Evolution Experiment (Majewski
et al. 2015, submitted);
RAVE = RAdial Velocity Experiment (Kordopatis et al. 2013, cat. III/272);
SEGUE = Sloan Extension for Galactic Understanding and Exploration
(see Yanny et al. 2009, cat. J/AJ/137/4377).
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 26-Apr-2016