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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Drullinger, R.E.,Wineland, D.J. and Bergquist, J.C.: 1980, Appl. Phys. 22, 365.
Dzuba, V.A., Flambaum, V.V., Kozlov, M.G. and Marchenko, M.: 2002, Phys. Rev. A 66, 022501.
Gay, P.L. and Lambert, D.L.: 2000, Astrophys. J. 533, 260.
Hallstadius, L.: 1979, Z. Phys. A 291, 203.
Murphy, M.T., Webb, J.K., Flambaum, V.V., Churchill, C.W. and Prochaska, J.X.: 2001a, Mon. Not. Roy. Soc. 327, 1223.
Murphy, M.T., Webb, J.K., Flambaum, V.V. and Curran, S.J.: 2002, astro-ph/0209488.
Murphy, M.T., Webb, J.K., Flambaum, V.V., Dzuba, V.A., Churchill, C.W., Prochaska, J.X., Barrow, J.D. and Wolfe, A.M.: 2001b, Mon. Not. Roy. Soc. 327, 1208.
Rosman, K.J.R. and Taylor, P.D.P.: 1998, J. Phys. Chem. Ref. Data 27, 1275.
Timmes, F.X. and Clayton, D.D.: 1996, Astrophys. J. 472, 723.
Webb, J.K., Murphy, M.T. and Flambaum, V.V.: 2002, in: C.J.A.P. Martins (ed.), The Cosmology of Extra Dimensions and Varying Fundamental Constants, Netherlands, Kluwer.
Webb, J.K., Murphy, M.T., Flambaum, V.V., Dzuba, V.A., Barrow, J.D., Churchill, C.W., Prochaska, J.X. and Wolfe, A.M.: 2001, Phys. Rev. Lett. 87, 091301.
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Murphy, M., Webb, J., Flambaum, V. et al. Does the fine structure constant vary? A detailed investigation into systematic effects. Astrophysics and Space Science 283, 577–582 (2003). https://doi.org/10.1023/A:1022570532369
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DOI: https://doi.org/10.1023/A:1022570532369