More fine structure constant …

A chance to gloat after reading this paper  on astro-ph: Impact of instrumental systematic errors on fine-structure constant measurements with quasar spectra by Whitmore & Murphy, in which they conduct an in-depth calibration study of systematic distortions in high-resolution spectrographs and use a simple model of these distortions to simulate systematic errors in the Keck and VLT observations used by Webb et al. (2011) and King et al. (2012) to claim evidence for a cosmic dipole in alpha.  From the abstract, “The spurious deviations in alpha  produced by the model closely match important aspects of the VLT–UVES quasar results at all redshifts and partially explain the HIRES results, though not self-consistently at all redshifts. That is, the apparent ubiquity, size and general characteristics of the distortions are capable of significantly weakening the evidence for variations in alpha from quasar absorption lines.”  Which is interesting because the absolute implausibility of any such systematics was the basis by which Julian King’s referee report argued for rejecting my second fine structure paper despite the Bayes factor significantly favouring the systematic error model!

Now to enjoy Figure 15 from Whitmore & Murphy comparing their simulations of the systematics in the historical VLT data with the changes in fine structure constant claimed in the quasar dataset used by Webb et al. (2011) and King et al. (2012) …
vlt

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2 Responses to More fine structure constant …

  1. lukebarnes says:

    Aw shucks. A varying fine structure constant would have been pretty interesting. Ruined by statistics, as usual …

  2. And then there’s this today:
    http://arxiv.org/abs/1409.5738
    From Planck: “This [Ed: the dust power] is the same magnitude as reported by BICEP2 over this ℓ range”

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