J/AJ/141/90 SEGUE stellar parameter pipeline. V. (Lee+, 2011)
The SEGUE stellar parameter pipeline.
V. Estimation of α-element abundance ratios from low-resolution SDSS/SEGUE
stellar spectra.
Lee Y.S., Beers T.C., Prieto C.A., Lai D.K., Rockosi C.M., Morrison H.L.,
Johnson J.A., An D., Sivarani T., Yanny B.
<Astron. J., 141, 90 (2011)>
=2011AJ....141...90L 2011AJ....141...90L
ADC_Keywords: Surveys ; Abundances ; Spectroscopy ; Effective temperatures
Keywords: methods: data analysis - stars: abundances -
stars: fundamental parameters - surveys -
techniques: imaging spectroscopy
Abstract:
We present a method for the determination of [α/Fe] ratios from
low-resolution (R=2000) SDSS/SEGUE stellar spectra. By means of a
star-by-star comparison with degraded spectra from the ELODIE spectral
library and with a set of moderately high-resolution (R=15000) and
medium-resolution (R=6000) spectra of SDSS/SEGUE stars, we demonstrate
that we are able to measure [α/Fe] from SDSS/SEGUE spectra (with
S/N>20/1) to a precision of better than 0.1dex, for stars with
atmospheric parameters in the range Teff=[4500,7000]K, logg=[1.5,5.0],
and [Fe/H]=[-1.4,+0.3], over the range [α/Fe]=[-0.1,+0.6]. For
stars with [Fe/H]←1.4, our method requires spectra with slightly
higher signal-to-noise to achieve this precision (S/N>25/1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 82 425 List of parameters for selected ELODIE spectra
table2.dat 137 91 List of parameters for HET and ESI spectra
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See also:
J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008)
J/AJ/136/2070 : SEGUE stellar parameter pipeline. III. (Lee+, 2008)
J/AJ/141/89 : SEGUE stellar parameter pipeline. IV. (Smolinski+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name HD identification number
11- 15 I5 --- ELODIE ELODIE identification number
17- 20 I4 K Teff1 ELODIE effective temperature
22- 25 F4.2 [cm/s2] logg1 ELODIE log surface gravity
27- 31 F5.2 [Sun] [Fe/H]1 ELODIE metallicity
33- 38 F6.2 [Sun] [a/Fe]1 ELODIE α abundance
40- 43 F4.2 [Sun] e_[a/Fe]1 ? Uncertainty in [a/Fe]_1 (1)
45- 49 F5.3 [cm/s2] logg2 SSPP log surface gravity (2)
51- 55 F5.3 [cm/s2] e_logg2 Uncertainty in logg2
57- 63 F7.3 [Sun] [Fe/H]2 SSPP metallicity
65- 69 F5.3 [Sun] e_[Fe/H]2 Uncertainty in [Fe/H]2
71- 76 F6.3 [Sun] [a/Fe]2 SSPP α abundance
78- 82 F5.3 [Sun] e_[a/Fe]2 Uncertainty in [a/Fe]2
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Note (1): Note that if only [Mg/Fe] is available from the published
studies, no error in [α/Fe] is reported, and that there are
multiple observations made for some stars. There are 293 unique stars
out of 425 spectra.
Note (2): SSPP = SEGUE Stellar Parameter Pipeline
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- P-M-F SDSS Plate-MJD-Fiber identification
16- 19 A4 --- --- [SDSS]
21- 39 A19 --- SDSS SDSS Designation (JHHMMSS.ss+DDMMSS.s)
41- 44 I4 K Teff1 High-Resolution analysis effective
temperature
46- 48 I3 K e_Teff1 Uncertainty in Teff1
50- 54 F5.3 [cm/s2] logg1 High-Resolution analysis log surface
gravity (1)
56- 60 F5.3 [cm/s2] e_logg1 Uncertainty in logg
62- 67 F6.3 [Sun] [Fe/H]1 High-Resolution analysis metallicity (1)
69- 73 F5.3 [Sun] e_[Fe/H]1 Uncertainty in [Fe/H]1
75- 80 F6.3 [Sun] [a/Fe]1 High-Resolution analysis α abundance
82- 86 F5.3 [Sun] e_[a/Fe]1 Uncertainty in [a/Fe]1
88- 91 I4 K Teff2 SSPP effective temperature (1)
93- 95 I3 K e_Teff2 Uncertainty in Teff2
97-101 F5.3 [cm/s2] logg2 SSPP log surface gravity (1)
103-107 F5.3 [cm/s2] e_logg2 Uncertainty in logg2
109-114 F6.3 [Sun] [Fe/H]2 SSPP metallicity (1)
116-120 F5.3 [Sun] e_[Fe/H]2 Uncertainty in [Fe/H]2
122-127 F6.3 [Sun] [a/Fe]2 SSPP α abundance (1)
129-133 F5.3 [Sun] e_[a/Fe]2 Uncertainty in [a/Fe]2
135-137 A3 --- Ref [HET ESI] Facility of high-resolution:
HET = Hobby Eberly Telescope, or
ESI = Keck Echellete Spectrograph and Imager
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Note (1): Teff in the SSPP columns is delivered by the SSPP (SEGUE
Stellar Parameter Pipeline), whereas logg, [Fe/H], and [α/Fe]
come from the method described in this paper. The gravity and
metallicity of the high-resolution analysis are estimated from the
technique addressed in S 3.2.
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History:
From electronic version of the journal
References:
Lee et al., Paper I 2008AJ....136.2022L 2008AJ....136.2022L
Lee et al., Paper II 2008AJ....136.2050L 2008AJ....136.2050L, Cat. J/AJ/136/2050
Allende Prieto et al., Paper III 2008AJ....136.2070A 2008AJ....136.2070A, Cat. J/AJ/136/2070
Smolinski et al., Paper IV 2011AJ....141...89S 2011AJ....141...89S, Cat. J/AJ/141/89
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 01-Aug-2012