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We statistically analyse a recent sample of data points measuring the fine-structure constant alpha (relative to the terrestrial value) in quasar absorption systems. Using different statistical techniques, we find general agreement with previous authors that a dipole model is a well-justified fit to the data. We determine the significance of the dipole fit relative to that of a simple monopole fit, discuss the consistency of the interpretation, and test alternate models for potential variation of alpha against the data. Using a simple analysis we find that the monopole term (the constant offset in (delta alpha)/alpha) may be caused by non-terrestrial magnesium isotope abundances in the absorbers. Finally we test the domain-wall model against the data.
The brightest southern quasar above redshift $z=1$, HE 0515$-$4414, with its strong intervening metal absorption-line system at $z_{abs}=1.1508$, provides a unique opportunity to precisely measure or limit relative variations in the fine-structure co
We present a new `supercalibration technique for measuring systematic distortions in the wavelength scales of high resolution spectrographs. By comparing spectra of `solar twin stars or asteroids with a reference laboratory solar spectrum, distortion
Quasar absorption spectral data indicate the presence of a spatial gradient in the electromagnetic fine-structure constant $alpha$ on cosmological length scales. We point out that experiments with accelerometers, including torsion pendula and atom in
A new and automated method is presented for the analysis of high-resolution absorption spectra. Three established numerical methods are unified into one artificial intelligence process: a genetic algorithm (GVPFIT); non-linear least-squares with para