Access to Astronomical Catalogues

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
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:

       FileName      Lrecl  Records   Explanations

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


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

   Bytes Format Units   Label     Explanations

   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

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



Byte-by-byte Description of file: table2.dat

   Bytes Format Units     Label     Explanations

   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

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.


History:
    From electronic version of the journal

References:
    Lee et al.,              Paper I    2008AJ....136.2022L
    Lee et al.,              Paper II   2008AJ....136.2050L, Cat. J/AJ/136/2050
    Allende Prieto et al.,   Paper III  2008AJ....136.2070A, Cat. J/AJ/136/2070
    Smolinski et al.,        Paper IV   2011AJ....141...89S, Cat. J/AJ/141/89
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    01-Aug-2012