Astrophysics and Space Science

, Volume 283, Issue 4, pp 577–582 | Cite as

Does the fine structure constant vary? A detailed investigation into systematic effects

  • M.T. Murphy
  • J.K. Webb
  • V.V. Flambaum
  • S.J. Curran
Article

Abstract

We have previously presented 5.7 σ evidence for a smaller αat redshifts 0.2 < zabs < 3.7 from a sample of 128 Keck/HIRES quasar absorption systems: Δα/α = (-0.57 ± 0.10) x10-5. A non-zero <Δα/α manifests itself as a distinct pattern of shifts in the measured absorption line wavelengths. The statistical error is now small: we do detect small line shifts in the HIRES data. Whether these shifts are due to systematic errors or due to real variation in α is now the central question. Here we summarize the two potentially most important systematic effects: atmospheric dispersion and isotopic abundance evolution. Previously, these have been difficult to quantify/model but here we find that neither of them can explain our results. Furthermore, the HIRES spectra themselves contain no evidence for these effects. Independent measurements of Δα/α with a different telescope and spectrograph are now crucial if we are to rule out or confirm the present evidence for a variable α.

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Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • M.T. Murphy
    • 1
  • J.K. Webb
    • 1
  • V.V. Flambaum
    • 1
  • S.J. Curran
    • 1
  1. 1.School of PhysicsUniversity of New South WalesSydney

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