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J/other/MmSAI/80.833  Variations of the fine-structure constant (Murphy+, 2009)
Keck constraints on a varying fine-structure constant:
wavelength calibration errors.
    Murphy M.T., Webb J.K., Flambaum V.
   <Mem. Soc. Astron. Ital., 80, 833-841 (2009)>
   =2009MmSAI..80..833M
ADC_Keywords: Atomic physics ; QSOs

Keywords: Instrumentation: spectrographs - Techniques: spectroscopic -
          Cosmology: observations - Quasars: absorption lines - Line: profiles

Abstract:
    The Keck telescope's High Resolution Spectrograph (HIRES) has
    previously provided evidence for a smaller fine-structure constant,
    α, compared to the current laboratory value, in a sample of 143
    quasar absorption systems:
    Δα/α=(-0.57±0.11)10-5. The analysis was based on
    a variety of metal-ion transitions which, if alpha varies, experience
    different relative velocity shifts. This result is yet to be robustly
    contradicted, or confirmed, by measurements on other telescopes and
    spectrographs; it remains crucial to do so.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        76      143   Values of Δ(α)/α and corrections
                              for possible intra-order distortions of the
                              wavelength scale
trans.dat         66       23   Transition codes, from Murphy et al.
                              (2003, Cat. J/MNRAS/345/609)


See also:
    J/MNRAS/345/609 : Variability of the fine-structure constant (Murphy+, 2003)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label   Explanations

   1-  9  A9    ---     Name    B1950 QSO name (HHMM-DDM)
  12- 16  F5.3  ---     zem     ?=- Emission redshift
  18- 24  F7.5  ---     zabs    Absorption redshift
  26- 39  A14   ---     Trans   Transitions used to determine da/a in each
                                 absorber (1)
  43- 48  F6.3  ---     da/a    Δα/α value (relative 
                                  variation of the fine structure constant)
  50- 54  F5.3  ---     e_da/a  Formal 1-sigma statistical error on da/a
  56- 60  F5.3  ---    d(da/a)  Systematic error on da/a (2)
  62- 67  F6.3  ---     da/aC   Estimate of the da/a correction, intra-order
                                 distortions, to be added to da/a
  69- 73  F5.3  ---   d(da/aC)  Systematic error term on da/acorr (3)
  75- 76  A2    ---     Sam     Observational sub-samples employed (4)

Note (1): Each letter represents a transition and the key is provided in
     trans.dat file, from table 2 of Murphy et al. (2003, Cat. J/MNRAS/345/609)
Note (2): is non-zero only for "high-contrast" absorbers; see text for
     explanation.
Note (3): which was calculated in the same way as delta(da/a)_sys but using
     the corrected values of da/a.
Note (4): Sub-samples codes as follows:
     A  = "Previous low-z sample" from Murphy et al. (2003, J/MNRAS/345/609)
     B1 = "Previous high-z sample" from Murphy et al. (2003, J/MNRAS/345/609)
     B2 = The 15 absorbers added in Murphy et al. (2004, LNP, 648, 131)
     C  = "New sample" from Murphy et al. (2003, J/MNRAS/345/609)


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

   Bytes Format Units   Label     Explanations

       1  A1    ---     Trans     Transition code
   3-  8  A6    ---     Ion       Ion
  10- 19  F10.5 0.1nm   lambda0   Laboratory wavelength
  21- 41  A21   ---     Ground    Ground state
  43- 66  A24   ---     Upper     Upper state


History:
    Copied at http://astronomy.swin.edu.au/~mmurphy/MurphyM_09a.dat
(End)                                      Patricia Vannier [CDS]    25-Jan-2010