Michael Murphy (Swinburne University of Technology) - Possible cosmological variations in the fine-structure constant?: a status update

Large samples of archival high-resolution quasar spectra, from both Keck and VLT, have previously indicated possible evidence for cosmological variations in the fine-structure constant, alpha. While the data show an encouraging internal consistency, concluding that electromagnetism's strength really varies throughout the Universe would be extraordinary, so the evidence needs careful testing. We have pursued two main approaches: new quasar observations dedicated to the measuring alpha; and new, empirical tests to discover or rule out instrumental systematic effects, particularly relating to the wavelength calibration of echelle spectra. I'll report on these efforts, including new alpha measurements and potentially important systematic effects.